Mineral Resources

Contents

• Periodic Table of Elements• Mineral Resources• Standard classification of metals• Classification of deposit types (14)• Non-metals & Industrial Minerals• Mineral Collecting• Fireworks

• Gems & Gemstones• Gem deposits• Gems in Canada

Periodic Table of Elements

• Metals (copper)• Non metals (oxygen)• Alkali metals (sodium)• Alkaline earth metals (magnesium)• Halogens (chlorine)• Noble gases (helium)

Name of elements

• Discovered one by one • Some from the locality where they were found

first (Yttrium from Ytterby, Sweden)• Greek/ Latin roots in most names• Hydrogen= ydor, hydro (water) + gene

(creating)• Helium is the Greek word for the Sun, because

it was discovered there by the spectrum

• Lithium= Greek word for stone, because it comes from rocks not plants (like its neighbors on the Table)

• Oxygen= acid creator (erroneously thought)• Chlorine= means green-yellow• Nickel= from Old Nick meaning the Devil,

because you get no copper. They thought the reddish mineral would give Cu on smelting

• Molybdenum=  meaning  “lead”  or  “a  soft,  black  substance  that  can  be  used  for  writing”

• Antimony=  “instead  of  by  itself”  or  not  found  by itself, always mixed with other minerals

• Iodine= the color of violet (flower)• Lanthanum=  “easily  missed”  because  it  is  

hidden among other minerals• Gold= yellow

• Platinum=  “small  silver”  because  it  is  white  and usually found with gold

• Uranium= from planet Uranus, discovered at about the same time as the element

The Elements

• Arranged according to atomic number (size of atom)

• From element # 1 to element # 26 (Iron) manufactured by our Sun (the star)

• All higher than # 26 manufactured by supernova explosion of pre-existing stars

• Therefore, our solar system is second generation star system (attractive to aliens?)

The Periodic Table

• Tabular arrangement of elements• Atomic number is # of protons in the nucleus• Rows called periods, columns are groups• 18 columns, 7 rows with a double row below • 4 rectangular blocks: s-block to the left, p-

block to the right, d-block in the middle & f-block below

• The  table  incorporates  “recurring  trends”,  like  similar properties

• Table can also predict properties of new elements

• Atomic number is # of protons in the nucleus-equal to # of electrons

• A new row (period) is created when the atom has a new electron shell & has its first electron

• Elements with the same # of electrons in a particular shell occupy the same column

• Elements with similar properties belong to the same group

• Today, 114 confirmed elements• Only 98 elements occur naturally• There are 18 columns or groups

Can change one element to the next

• With a higher atomic number• Simply by giving it energy• If unstable, it will give off this extra energy –

doing some useful work – and change back to its original

• Example  from  “Jerusalem  Dome  of  the  Rock  UFO”• Flash is when it changes into a higher element,

then gives off its energy by climbing up fast while it changes back to its earlier form – the element created is probably element 116 which is unstable

Electronic equipment we use

• Necessary to have good conductors (metals)• Need special properties of conductors• Many of these are provided by the REEs• Rare Earth Elements: China has the bulk of

them, but others may have them too• Need exploration to find them

Where to find information

• Textbooks• Unfortunately, the textbook for this course is

out of print, new one not ready

Info on the web

• Mineral Resource Classification: Wikipedia• Ore Genesis : Wikipedia• Hydrothermal circulation: Wikipedia• Hydrothermal synthesis: Wikipedia• Volcanogenic massive sulfide ore deposit:

Wikipedia• Seafloor massive sulfide deposits: Wikipedia

Info on elements for project

• Look under name of element / metal• Look under deposit of that element / metal• Find something you like or you want to know

more about (such as the gems of Manitoba!)• Make a presentation and/or send by email

Where the metals come from?

• Every rock you pick has traces of metals, but you  can’t  see  them  – in trace amounts

• These metals can be absorbed by hot water solutions going through the rocks

• The solutions will also have other solvents like sulfur that can dissolve other metals

• When conditions change along the way the metals can be deposited – they precipitate out

Examples of changing conditions

• Change in temp. or pressure• Change in rock type

Metals

• Their abundance in rocks of various types has been measured

• In  order  for  them  to  become  “ore”  nature  has  to collect them in some place or trap

• This concentration over millions of years of time has created ore deposits

• The concentration factors of metals varies quite a lot

Concentration of metals into ore

• abundance concentration factor• Al 8.2% 4• Fe 5.6 % 9• Cu 55 ppm 180• Zn 70 ppm 700• Au 4 ppb 1250• Pt 5 ppb 1000

Magma

• Dissolves surrounding rocks • Within a liquid mass, some metals can

accumulate if they are heavier, for example• These  “heavies”  accumulate  at  the  bottom  of  

magma chamber and can solidify to form a layered deposit when magma cools down, for example, chromium, platinum

Human history and resources

• Stone Age• Copper Age – but Cu is soft• Bronze Age 3,000 BC – Cu + Sn (tin)• Iron Age 1,200 BC• Many new discoveries since industrialization ~

200 years ago

Mineral Resources

• Resources (available if feasible) v. reserves (ready to mine)

• Material of economic interest. Needs to be calculated, usually after drilling. Then, called “ore”

• Theories  on  how  materials  form  in  the  Earth’s  crust:  “ore  genesis”

• Material has a source, usually magma, then it is transported and deposited in a suitable environment (trap)

Ore genesis processes

• Inside the Earth: magmatic, hydrothermal, metamorphic

• On the surface of the Earth (example, gold nuggets in a river)

Concentration of metals

• One can get a clue of the mineralizing solutions from the so-called  “fluid  inclusions”  or remains of those fluids trapped in the rocks

Fluid Inclusions

• 4 common types• Aqueous: liquid + minor vapor• Aqueous: vapor + minor liquid• Aqueous; liquid, vapor, halite, anhydrite• CO2 – bearing

Compare them to our own blood

• Which passes through our body bringing nourishment, oxygen, etc & removing other substances

• (blood is a solution identical to the sea water)

• Most metal deposits are sulfides• But metal sulfides are extremely insoluble in

pure hot water• Evidence comes from fluid inclusions: small

samples of fluid trapped in minerals• Inclusions contain a lot of Na, Ca, Mg, Cl & S

and metals• Metals transported as soluble compounds,

such as PbCl2 + H2S = PbS + 2HCl

example

• Galena (PbS) precipitated when the lead compound comes in contact with hydrogen sulfide gas

Standard classification of metals

Common ores

• Iron• Lead-zinc-silver• Gold• Platinum• Nickel• Copper • Uranium

• Titanium and zirconium• Tin, tungsten and molybdenum• Rare earths, niobium, tantalum, lithium• Phosphate• Vanadium• Gems• Industrial minerals (sand, gravel,

diatomaceous earth, silica sand)

Iron (Fe)

• Mostly magnetite in ancient sediments accumulated on the ocean floor in an oxygen poor atmosphere and acidic water

• Weathering converts magnetite into hematite, much easier to process

• Some deposits within the Pilbara region of W. Australia formed as placer deposits

• They formed by accumulation of hematite gravels called pisolites, which form channel-iron deposits

Iron Formations

• Found in Proterozoic rocks (Precambrian) worldwide

• Large deposits in Ontario & Quebec• Small occurrences throughout Manitoba –

example, near Bissett• Big production in Michigan (cell phones may

not work in some places due to abundant magnetite deposits)

Lead-Zinc -Silver

• Form by the discharge of deep sedimentary brine onto the sea floor (SEDEX), or by replacement of limestone, some associated with volcanoes.

• Vast majority of SEDEX deposits are of Proterozoic age, some are of Jurassic age.

• The carbonate replacement type deposits form by degradation of limestone by hydrocarbons which are thought to be important for transporting lead

Pb-Zn-Ag

• The minerals are galena & sphalerite. Silver is found in inclusions within galena

• Silver-rich galena will have a striped appearance (see hand samples)

Gold (Au)

• Form in a very wide variety• Primary or placer or residual• Plate tectonics generates gold deposits• Primary are lode or intrusion-related • Lodes associated with orogeny or other

collision events• Most lode deposits sourced from

metamorphic rocks

• Form by dehydration of basalt during metamorphism

• Gold transported up faults by hydrothermal waters and deposited when the water cools too much to retain gold in solution

• Lode deposits are high-grade, thin, vein or fault-hosted. Usually in quartz veins or reefs

• Usually hosted in basalt or in sediments known as turbidites, although when in faults that may be in granite

• Intrusive-related gold hosted in granite, porphyry or dikes. May also contain copper, tin, tungsten, etc

• These deposits rely on gold existing in the fluids associated with the magma

• Placer deposits form via gravity with gold sinking into a trap or bends in rivers

Gold  “Reef”,  Quebec

East Malartic mine, Quebec

Next to the town of Malartic

Gold in a chert horizon

Laterite gold

• Form after prolonged weathering of primary gold deposits

• Example: Ketza deposit in the Yukon – see samples

Ketza river mine

Uses of Au

• For 70 years it was a standard treatment for rheumatoid arthritis to inject a liquid suspension of gold, which acts like an anti-inflammatory – no one knows why or how

• Windows coated with Au to help reflect the sun in the summer and retain heat in winter

• About 20 % of decorative gold is in the thread of Indian saris

Toronto’s  Royal  Bank  Plaza

• Two 41-and- 26 storey towers• Has 14,000 windows• All have very thin coating of 24-carat gold leaf• 2,500 ounces (70.8 kg) of gold worth over 1

million $

Can you change metal into Au?

• Soviet nuclear reactors transformed some lead nuclei into gold

220 oz X $1,500= $330,000

Gold in history

• World production from ancient times to now is about 165,000 tons

• A lot is reused• Biggest source of gold is in the ocean water, but  you  can’t  recover  it

• Alexander inherited 5,000 tons of gold –the bulk of the gold produced prior to zero year -when he conquered Persia (it brought its gold from Uzbekistan / Tajikistan, Persia had none)

• Egypt has many gold treasures, but the country has no gold – it brought it from Sudan

• The Incas of ancient Peru had lots of gold from the volcanic / igneous rocks of the Andes

• California  “started”  with  the  Gold  Rush,  later  a  “Yukon  Rush”  in  the  Klondike  area  (depicted  in  movies of Charlie Chaplin)

• Latest production comes from the shallow “black  smokers”  of  the  Pacific  ocean

Platinum (Pt)

• Pt and palladium are generally found within ultramafic rocks

• Source of the metals is rocks that have enough sulfur to form a sulfide mineral while the magma is still liquid

• The sulfide mineral (pyrite, etc) gains platinum by mixing with the bulk of the magma because Pt is chalcophile (it likes Cu) and is concentrated in sulfides

• Sulfide phases only form in ultramaficmagmas when the magma reaches sulfur saturation.

• To achieve sulfur saturation magma must get contaminated with sulfur-rich wallrock or mixed with other magma

• Often, Pt is associated with Ni, Cu, Cr and Co deposits

Most  of  world’s  production

• Comes from the Merensky Reef in South Africa, a continuous layer that formed by fractional crystallization within one magma chamber

• Minor production comes from Thompson, Man. and Norilsk, Siberia

• Pt used in seat belts – excellent conductor

Nickel (Ni)

• Two types, as sulfide or laterite• Sulfide form the same way as Pt deposits• Ni is a chalcophile element which prefers

sulfides, so an ultramafic or mafic rock which has a sulfide phase in the magma may form nickel sulfides.

• Best Ni deposits accumulate at the base of komatiite lavas (Mg-rich)

Thompson / Voisey Bay deposits

• Subvolcanic sills host Ni sulfide deposits formed by deposition of sulfides near the feeder vent. Sulfide was accumulated near the vent due to the less of magma velocity at the vent interface

Sudbury deposits

• The Sudbury Basin or the Sudbury Nickel Irruptive is a major geologic structure in Ontario

• It is the second largest impact crater on Earth as well as one of the oldest (1.8 b.y. old)

• The large impact crater filled with magma rich in Ni, Cu, Pt, Pd, Au & other metals

Norilsk deposits, Siberia• Largest Ni-Cu-Pd deposits in the world• Deposit formed 250 m.y. ago during the eruption

of the Siberian Trap Igneous Province (STIP). The STIP erupted over I million cubic km of lava, a large portion of it through a series of flat-lying conduits

• The ore formed when the erupting magma became saturated in sulfur, forming globules of sulfides.  These  sulfides  were  then  “washed”  by  the continuing torrent of erupting magma & upgraded their tenor with Ni, Cu, Pt & Pd

Rich Pt-Cu ore

Ni laterite deposits

• Similar to formation of gold laterites except that ultramafic or mafic rocks are required

• Very large olivine-bearing ultramaficintrusions

New Caledonia

Uses of Ni

• The Loonie: bronze plated on pure Ni (7 g wt)• In CDs, cell phones, batteries, electric shavers,

golf clubs, credit cards, etc

Copper (Cu)

• Either formed within sedimentary rocks or in igneous rocks

• Most major copper deposits within the granitic porphyry copper style

• Sedimentary Cu forms in ocean basins. Cu is precipitated by brine from deeply buried sediment (similar to SEDEX zinc)

Uranium (U)

• Source is radioactive granites when certain minerals like monazite are leached during hydrothermal activity or by circulation of groundwater

• U is brought into solution by acidic conditions & is deposited when this acidity is neutralized

• Generally this occurs in carbon-bearing sediments within an unconformity

• U also found in coal and in all granites• Radon gas creates a problem in U mining• 40% of world U in the Olympic Dam deposit in

Australia. U in granite & porphyry

Uranium City area, Sask.

• Production  from  1960’s  until  1982• Newer high grade deposits discovered under

the Athabasca sandstone Basin in N. Sask. have huge reserves & tremendous potential

• Unconformity with underlying basement is the target wherever graphite sediments are present

Canadian Shield

North American craton

Uranium properties/mines

Geology of the Basin

Unconformity U deposits

Rocks with uranium

Top:  “comb  quartz  crystalsbottom: fractured rock with many veins

Titanium & Zirconium (Ti, Zr)

• Mostly found as mineral sands• By accumulation of heavy minerals in beaches

(like placer)• Titanium as ilmenite, rutile & leucoxene• Zirconium as zircon• Thorium in monazite• All found in granite. After erosion &

transportation by rivers into beaches

Zircon

• Yellow grains in granite• Contains U, Th• Used as a opacifier (make things opaque) in

ceramics

Tin, tungsten & Molybdenum

• Form in certain type of granites• Skarn deposits form by reaction of mineralized

fluids with the rocks – such as limestone -surrounding the granite

Tin

• To make tin cans• Making bronze• Now only produced in Malaysia from alluvial

deposits

Tin veins in granite, Cornwall, UK: details later on

Tungsten

• Heavy metal, rare in nature• Used in steel, carbide, lamp filaments

Molybdenum

• Found with Cu in porphyry deposits• Used in making steel

Rare Earths, Niobium, Tantalum, Lithium

• The majority of REEs +tantalum & lithium-found within pegmatite

• Probable origin by metamorphism & igneous activity

• Lithium as spodumene & lepidolite• Carbonatite intrusions an important source of

these elements

Bernic Lake, Manitoba: Tanco mine

• Lithium• Cesium  (80%  of  world’s  production)  • Tantalum • Columbium• Beryllium

Hoidas Lake, N. Sask.

• 50 km north of Uranium City• Most advanced REEs property in Canada

(ready for mining)• Named after a WWII pilot who died in action• Contains a significant amount of heavy REEs,

such as dysprosium- used in hybrid car components

• Unfortunately, there is some U in the ore

Phosphate

• Used as fertilizers• Immense quantities in sedimentary rocks from

the Proterozoic age to now• The source of P is the skeletons of marine

animals• Another source is intrusions like nepheline

syenite & carbonatites• The P is in apatite & monazite

Vanadium (V)

• Found in blood cells of vanabins in the sea• Biological processes responsible for the

deposits• Also found in crude oil & oil sands• Added to iron to make steel

Tellurium (means from the earth) has accomplished:

• Cheaper photovoltaics• More robust CDs• Spectacular pictures from the Hubble

telescope• However, when you work with the metal it

enters body and for many months your sweat, urine has a garlic smell!

Classification of deposit types

ORE DEPOSIT MODELS

• 14 types

1.Layered mafic-ultramafic intrusions

• Intrusions with Ni-Cu sulfides at the base• Fractional crystallization with density

stratification• Chromite-rich layers (Cr) – Bird River, Man.• Other metals: Pt group elements• Cross Lake: magnetite with Ti

2.Carbonatite Alkaline intrusions: REEs

• Igneous intrusions made up of calcite-dolomite-ankerite with apatite & magnetite

• Alkaline (Na and K rich) volcanic rocks• Related to continental rifting & alkaline

volcanism• REEs: Ce, Y, La, Sm, Eu

Example from Montreal area

“mounts”  with  various  rock  types

Mont St. Hilaire, Que.

• One of the Monteregian hills• Has 3 distinct intrusions: gabbro, nepheline

syenite with pegmatites• Famous mineral locality- rare & exotic• 366  minerals,  50  of  which  are  “endemic”  (type  

location) • Most Fe-rich biotite in the world

Hill with spa

Carletonite : type locality

Rare Earth minerals

Purple syenite complex

“Mounts”  around  Montreal

Lac St. Jean area: Niobec mine

Syenite pegmatite

3. Porphyry Copper intrusions

• Porphyritic granitic rocks with a network of chalcopyrite veins

• At collision of plate boundaries of Andean type or island arcs – mountains today

• Alteration zones with inner potassic, outer sericite & peripheral chlorite-epidote

• Fluids from the pluton followed by later lower temp. fluids leaching Cu & S from the magma & surrounding rocks

Porphyry copper deposits

Cross section

Alteration zones

Example: Cerro Colorado, Panama

The deposit is the whole mountain

Paths are for exploring & moving drill

Platforms are for drilling

Steep terrain

Paths 100 m apart vertically

Camp in the valley

Old volcano in the distance

Geologist

House of natives, this guy had 9 daughters

Armed forces paid a visit

Office and core shack

My map: red is porphyry, green is granite

3D of deposit

Cerro Colorado Cu-Mo deposit

• Cu –Mo not visible on surface, they have been oxidized and removed from near surface

• The  “country  rock”  is  basalt  that  deposited  on  the ocean floor

• Two main intrusions: a porphyry (red on map) and granite (green). Both are mineralized with a network of veins carrying chalcopyrite (yellow) and molybdenite (bluish) and minor pyrite

Alteration zones• The distribution of the Cu-Mo follows the

alteration pattern• Higher grades are in the potassic & sericite zones

and lower grades in the chlorite/calcite/epidotezone

• There seem to be two separate deposits that formed by the two different intrusions of the area (porphyry & granite)

• One of the biggest in the world with reserves over 3 b.tons (reserves calculated down to sea level). Highest elevation is 1,600 m

Made headlines in Northern Miner

2 of the geologists & the boss in NFLD

The deposit does not reach surface

Protests are numerous

4. Complex Pegmatites

• Late stage of granitic intrusions that have undergone fractional crystallization

• The last fraction of the magma would be rich in water & incompatible elements that could not fit into the earlier formed minerals

• Li, Be,B,F, Rb, Cs, REE, Th, U, Ti, Zr, Hf, Sn,Nb

5. Massive sulfides – Cyprus type

• Massive pyrite with Cu & Zn sulfides in pillow basalt (ophiolite)

• The ophiolite represent portions of the ocean crust formed at mid-ocean ridges. Seawater circulates through fractured basalt & heated to  400’  C,  while  metals  are  leached  from  basalt and deposited on ocean floor

• Part of ocean floor is preserved by thrusting onto adjacent continent

Cyprus:  origin  of  the  word  “copper”

6. Cu-Zn felsic volcanic deposits

• Cu & Zn in marine volcanic rocks• In island arcs related to subduction zones• Examples in Japan, Ontario, Quebec

7. Uranium clastic sedimentary deposits

• In permeable sandstone that cemented later• U from volcanoes

8. Mississippi Valley carbonate Pb-Zn

• Galena, sphalerite, chalcopyrite in porous rocks related to reefs

• In dolomite & breccias• Epigenetic ore (after the rock formed)• Cambrian to Carboniferous• Metals from basement. Low-temperature

fluids & highly saline with sulfur

Example: Pine Point, NWT

Open pit operation

Pine Point deposits

Galena

Samples showing

• Galena – sphalerite with calcite/dolomite• Pockets of sulfur• Pockets of bitumen• The host rock -limestone/dolomite- has been

altered by the mineralizing fluids• When you hit the rock with the hammer it

smells gasoline (it contains petroleum/oil from remains of marine animals like corals)

9. Banded Iron Formations

• Layered with chert• Great lateral extent• Deposited in shallow water (shelf)• Mostly Proterozoic in age• High dissolved content of SiO2 and Fe+2 in

seawater from leaching sea volcanoes

10. Aluminum Ore- bauxite

• Weathering over any aluminum-rich rock (granite)

• Mainly Cenozoic• Clay minerals associated with hematite, limonite• Tropical climate promotes breakdown of

feldspars into clays rich in Al. Silica, Iron & other solubles leached out

• ALCAN: Canadian co. has smelter in Kitimat, BC

bauxite

bauxite

11. Placer deposits: Au, Diamonds & heavy minerals

• Pt, Au, diamonds, magnetite, chromite, ilmenite, cassiterite, zircon

• Concentration in low-energy areas of stream flow (inner curves of meanders)

World’s  largest  nugget

12. Tin vein –Cornwall type

• Quartz-cassiterite (+/- Tungsten, base metals) veins associated with granite

• Intrusions in fold belts or collision of continents

• Similarities with porphyry coppers with alteration patterns

• Oxides within granite and outer sulfides of Cu, Zn, Pb, antimony

Cornwall, U.K.

• Southwest corner of England• People are Celts that have worked the tin

mines for ~ 2,500 years• Production from here responsible for Bronze

Age• Ancient Greek mariners called the British Isles “the  Cassiterides”  which  means  the  Tin  Islands

• In  the  1800’s  more  than  300  mines,  declined  slowly, none left today

• The miners moved to California, S.Africa & Australia. Some into Ireland where they call them “Tinkers”  prob.  because  they  worked  with  tin.  The  Irish  don’t  like  them,  treat  them  like  the  gypsies. Their graves are spectacular & spend a fortune on them – see pictures

• The Cornish recently became semi-independent and have their own language (Kernow)

• Local products: Cornish pasties, clotted cream

Tinkers’  graves

Granite (red), killas (brown), veins (yellow)

Cornish words

• Killas is  their  word  for  “country  rocks”  or  local  rocks

• Elvans is how they call the dikes or small intrusions like walls

• Mine  names  usually  start  with  “Wheal”,  like  Wheal Jane is one of them

Tin ore

Tin veins

13. Mercury – Almaden type (Spain)

• Stratabound disseminated cinnabar (HgS) & native mercury in volcaniclastic sedimentary rock

• Permeable sedimentary rocks near volcanic center with faulting

• No metamorphism or granite intrusion• Modern hot springs are associated with Hg

deposits suggesting ancient deposits formed by circulating hot fluids along faults, with the volcanic rocks acting as the source of the Hg

• Low solubility of Hg compounds requires very large amounts of fluid. Hot springs may provide such an environment

• Hg has a low boiling point, it may be transported as a vapor & deposited as pure (native) Hg

Mercury (quicksilver) ore

14. Nickel laterite deposits

• Deep weathering of ultramafic rocks in warm humid climate

• Enriched in Ni, Co, Cr• Alteration from top down, red & yellow soil

(limonite), saprolite, altered ultramafic rocks

Another classification

Abundant Metals

• Al• Fe• Mg• Ti

Scarce Metals

• Base metals: Zn, Cu, Pb, Sn, Cd, Hg• Ferroalloys : V, Cr, Ni, Co, Mo, W, Mn• Precious metals: Au, Ag• Platinum group metals: Pt, Pd• Rare Earth metals

Lightest & Heaviest

• Lithium v. Uranium

Non-metals & Industrial minerals

• Limestone, clays, sand, gravel, diatomite, silica, barite, gypsum, talc, perlite, zeolites, etc

• Used in construction, ceramics, paints, electronics, filtration, plastics, glass, detergents, paper, agriculture, etc

Fertilizers

• Nitrogen• Phosphorus• Potassium• Sulfur

Evaporites

• Potash • Salt (halite)• Gypsum & Anhydrite• Borates• Sodium sulfate

Potash

• ~  30  %  of  world’s  supply  from  Sask.• Reserves for centuries• One danger: flooding by water• 1 km deep layers within sedimentary rocks• Devonian age deposited in a cut-off portion of

the ocean

Salt (halite)

• Groundwater down to about a 200 m depth is fresh

• Below that it is saline (brine)• An anomaly (man-made or not) can bring

saline water higher up – like south of Winnipeg

Salt in Manitoba

Salts in the Prairies

Gypsum

• Making gyprock (drywall, plasterboard)• Raw gypsum is heated and water driven off,

then partially re-hydrated, wet product then sandwiched between two heavy sheets of paper and dried

Barite (means  “heavy”)  & usage

• Has a SG of 4.5 (~ double of ordinary rock)• In drilling muds• In pigments, paper industry• In playing cards (denser) – easier  to  “deal”• Blocks X rays & gamma rays

Silica sand (mostly quartz)

• Many, many uses• Found in deposits of sand in non-tropical

areas• Making glass, concrete, sandblasting,

industrial casting, etc• Fine quartz, however, is dangerous if inhaled

(silicosis)

Silicon Valley, California

• South part of San Fransisco• Silicon chip semiconductor used in high

technology operations (computers)• 1/3 of venture capital in the USA raised here• Best place for high tech jobs in the USA• Many universities• Specialists recruited/come from around the

world

The many uses of Fluorite

• Making glasses, enamel & ceramics• Non-stick Teflon cookware• In production of steel as flux –removes sulfur• Has exceptional optical clarity & used as

lenses that show extremely sharp image- for cameras, microscopes & telescopes

Sulfur• Bright yellow crystals at room temperature• Can react as either an oxidant or reducing• Common as sulfide of metals or sulphate• Brimstone (burn stone) used as fumigant• Rotten egg smell (hydrogen sulfide & SO2)• Responsible for smell in cabbage, broccoli, garlic,

onion & skunk• In proteins, aminoacids• In Canada, byproduct of natural gas, petroleum &

Tar Sands

Carbon

• All Life is carbon based (organic chemistry)• Element known since ancient times• Diamond & graphite (good conductor)• Found in limestone, CO2 gas & methane CH3• Forms more compounds than any other element,

more than 10 million• Has no melting point, it sublimes• Forms carbides (extremely hard) with tungsten

• In order to form Life, carbon needs to get scattered in space as dust from supernova explosions and then later incorporated into a 2nd or 3rd generation star (our Solar System is 3rd)

Graphite

• Both USA & EU declared graphite as a strategic mineral

• Important in high technology & green energy• 80% produced in China, however, reserves are

declining

Many uses

• Refractories• Batteries • Brake linings• Steel making• Laptop computers

Manganese

• World’s  healthiest  foods  rich  in  Mn (cloves, oats, rye, spinach, etc)

• We need small amounts in diet• Primary use in making steel• Not found in native (pure) state, usually

associated with iron• Name from Magnesia, Greece, confused with

magnetite, but Mn NOT magnetic

• Found on the ocean floor as nodules, but too difficult to mine, est. 500 billion tons

• Can have neurological problems if too much in the body from drinking water, etc

• Used as additive to gasoline (instead of lead)

Selenium (=moon)

• Found with sulfur• Used in electronics, glassmaking & pigments• Used in medical pills (thyroid problems) &

infant formula• Many thyroid problems in Europe after the

Yugoslavia war of 2001 when U bombs were used for first time

Neon

• One of the noble gases• Inert, not reactive gas• 5th most abundant element in the Universe

after H, He, C, O• Has a notably bright red light• Used in advertizing signs

Aggregates

• Sand & gravel• Crushed stone• Cement

Dimension stone

• Limestone – common in Manitoba• Granite – expensive, mostly as counter top• Gneiss – expensive, mostly as counter top• Peridotite – green with marble-like finish,

Winnipeg Convention Center• Granite porphyry – Regina Government

buildings

Limestone / dolomite/cement

Quicklime or calcium oxide (CaO)

• Calcium oxide is obtained by heating limestone at more than 825 degrees C to liberate carbon dioxide gas

• If left alone it can grab CO2 from the air to form limestone again

• If  quicklime  is  heated  to  2,400’C  it  emits  an  intense glow, called limelight; was used in old theatres before the advent of electricity

• Quicklime is the main ingredient to make cement

(Portland) cement

• Bricklayer Joseph Aspdin of Leeds, England first made cement early in 19th cent. by burning powdered limestone and clay in his kitchen stove

• To make cement today we use limestone, clay, silica sand and iron ore. They are heated at high temp. and form a rock-like substance that is ground into the extremely fine powder we call cement

cement

• Cement is mixed with water to make mortar• Or mixed with sand, gravel and water to make

concrete

Other uses of CaOsome info from visit to Limestone Quarry

• To neutralize acidity in base metal mines, like in Flin Flon who are treating sulfide-rich ore (acidic)

• With water it gives out a lot of energy, so it can be used for on-the-spot food warming

• Farming to neutralize acidity in soil• In pulp mills• In petroleum industry

Rock/Mineral collecting in Canada

• 130 clubs • Bancroft, Ontario: 1 of only 3 in the world,

where ancient conditions created nearly every known volcanic & metamorphic rock & mineral

• Mont-St-Hilaire, E of Montreal – among the top 10 in the world sporting 366 minerals

• Bay of Fundy: endless varieties of agate also zeolite & amethyst

• Thunder Bay: abundant amethyst, even the highways are purple in color. Also agate

• Souris pit: agates & petrified wood

Bancroft, Ont.

• Major attraction is the mineral-rich pegmatites. They are like magma that could not come to the surface as lava, instead it cooled at depth slowly

• Rose quartz (color due to Al?) is prominent• Apatite, sodalite, rare earths, uraninite, zircon• Marble was used across the country

Feldspars, a major product

• Part of ceramics, enamel, pottery• To make paints, soaps, roofing, tiles• Its highest grade to make false teeth• Its lowest grade in whipping up stucco

The elements in FIREWORKS

• Ancient Chinese used a mixture of sulfur, saltpeter and charcoal that was very flammable and would explode if put in a miniature amount of space. That was 7th cent.

• However,  at  the  same  time  the  “Greek  Fire”  was invented in 672 AD. Although its composition was a state secret and remained so, it must have been a mixture of things like pine resin, naphtha, quicklime, sulfur & niter

The  “Greek  Fire”  – in  Greek,  “liquid  fire”

Clay grenades filled with Greek Fire

Anatomy of fireworks: many parts

• A launching tube, 3 X the length of the fireworks shells, but exactly the same diameter

• When the gunpowder ( 75% saltpeter, 15% charcoal, 10 % sulfur) burns, the heat and gas are trapped & force their way to the surface until an explosion happens & they become airborne

• A fuse

Ingredients

• An oxidizer, a reducing agent, a coloring agent, binders and regulators

• Oxidizers (chlorate) produce the oxygen to burn the mixture

• Reducing agents burn the oxygen to make hot gases

• Binders hold the mixture in a lump

Incandescence & luminescence

• The light produced from heat is incandescence• Ti & Al used to increase the temp. & cause the

firework to burn brighter• Light produced by energy sources other than

heat is luminescence• Energy absorbed by an electron will cause it to be  excited.  When  the  electron’s  energy  is  lowered it is released as light

Colors

• Cu creates blue• Al to give silver & white colors & sparks• Zn makes smoke clouds• Ba for green, Sr, Li for red, Mg for white, Na

for gold & yellow• Cl brightens the colors

Fluorescent Minerals• UV radiation generated by a uv lamp• About 15% of minerals respond well to longwave

uv energy• Named after fluorite, the 1st mineral to show it• Longwave LED (Light-emitting Diode) lights are

popular, they generate less heat than ordinary ones

• You  can’t  look  directly  into  uv light,  it’s  like  looking at the sun

• Also uv light burns the skin

Fluorescent minerals

GEMS & gemstones

• Have intrigued people for the last 7,000 years• The first known were amethyst, rock crystal,

amber, garnet, jade, jasper, coral, lapis lazuli, pearl, serpentine, emerald and turquoise

• Were reserved for the wealthy as status symbols. Sealed documents had jewel-encrusted seals

• Had a mystery, spiritual & were worn as amulets. They could repulse evil, preserve health

Warning!

• Imitations of gems with synthetic varieties are widespread today

• You can easily be fooled by merchants

• Up to the beginning of 19th cent. used as medicine against illnesses

• Even today calcium tablets made out of powdered pearls are sold for medicinal purposes in Japan

• Linked to astrology and allocated to zodiac as birthstones

• Priests, bishops and kings wear them

Austrian crown recovered in Winnipeg in 2007!

• A strange bank robbery on Empress St. in 1998 surprised police who conducted a world-wide search that ended in a St. James home where the Austrian jewel-encrusted broach – the Koechert Pearl Diamond of the Empress of Austria- was found. It had been stolen 9 years before

• A very sophisticated robbery

Precious & semi-precious stones

• In the past were only a few, now many• Most are minerals• No official list• Semi-precious are softer stones• Profusion of names, some created to boost

sales, examples are tanzanite (blue zoisite) and tsavorite (green garnet)

Physical properties

• Crystal structure• Crystals grow in the available open spaces in the

rocks, so they take up various shapes• Hardness: most gems are hard• Specific gravity• Color (can be modified or changed)• Refractive index & double refraction• Inclusions  (old  “flaws”)- may boost price• Mining still primitive (except for diamonds)

Gem deposits

• Rare, because the conditions that promote their formations are unusual and thus worthy of scientific study

• Basically, if you want to prospect for gems go to the mountains or eroded mountains, like in Manitoba

GEM deposits

• Can be classified according to environment of formation or present location

• 1. Magmatic • 2. Hydrothermal • 3. Metamorphic • 4. Sedimentary • 5. Placer Some can be found in more than one class

1. Magmatic

• Diamonds found within volcanic kimberlite –names from Kimberley, S. Africa- and lamproite – Argyle mine in W. Australia

• Vertical pipe-like bodies called diatremes• Kimberlite forms from a very explosive

volatile-rich (high pressure) magma that forms ~ 150 km below the surface. As it travels upwards it fractures surrounding rocks, so kimberlite has many xenoliths (foreign rocks)

Canada’s  1st mine at Ekati, NWT opened 1998Currently,  world’s  3rd biggest producer: CanadaArkansas  has  a  “diamond  park”  open  to  the  

public (finders-keepers). The eroded surface of an ancient volcanic pipe, 95 m.y. old

• Biggest ever found: Cullinan at 3106 carats, the  “Star  of  Africa”  – polished 530 carats

• 2nd biggest from same mine, Cullinan II, at 545 carats- polished 317 carats

• Largest diamond in Canada came from the Attawapiskat mine at 35 carats

• Canadian  diamonds  are  also  called  “conflict-free”,  but  don’t  tell  that  to  the  Attawapiskatees

Attawapiskat

The rough Cullinan

Sapphires(name  means  “blue  stone”  originally  used  for  lapis)

• Yellow/green/pink/blue varieties of corundum• Formed deep inside the crust & were brought

in basaltic magma. However, they are rare• Economic deposits only found when basalt is

weathered & eroded away, leaving behind the heavier minerals such as sapphires & zircons which become concentrated in placer deposits

Corundum Al2O3

• Sapphire and Ruby• Second hardest mineral / substance• Synthetic corundum used in optical scanning

devises like grocery store checkout counters• Originate in marble / gem gravel deposits• Source thought to be basalt• Ruby can have unique asterism aspect

Madagascar

• One of the poorest countries in the world• > 50 % of population below poverty line of

$1/day (World Bank)• Has one of the largest gem deposits on the

planet• The sapphire trade links some of the poorest people  to  some  of  the  world’s  richest  people

• Temporary communities hunt along rivers & keep moving

Canada’s  1st  sapphire

• On Baffin Island, Nunavut• Sampled in 2004 yielded 142 grams• One stone (picture) produced a 1.17 carat

sapphire gem – the first in Canada

Ruby

• Can also be classified under metamorphic or placer

Ruby

Other magmatic

• Peridot: olivine found in mantle xenoliths• Labradorite: in basalt• Zircon: in granite/basalt/carbonatite• Apatite: in carbonatites• Garnets: in basalt /granite/gneiss

Peridot (olivine)

• Found in lavas and rocks from the mantle• Can be mistaken for an emerald• Can also be found in meteorites (pallasites)• Largest gem is 310 carats• A 3 to 4 carat stone sells for $ 40 – 80

Labradorite

From Madagascar

• Type  location  is  in  Paul’s  island,  Labrador,  but  also found in other places

• Found in basalt and gabbro• Iridescence produced within crystals of feldspar  by  light  diffraction  between  “layers”

• A pendant, 26 X 40 mm sells for $35

Zircon

Apatite

2. Hydrothermal deposits

• Most gemstones formed from volatile-rich fluids in pegmatites

• Opal, turquoise• Li & B –rich form tourmaline• F-rich form topaz• Be-rich form beryl or aquamarine• Emerald, also from Be-rich fluids

• Volcanic opal also from fluids. It contains many inclusions of water & cracks easily

• Ancient mines in Slovakia worked for 2,500 years. Found in Nevada, Mexico & Australia

• Amethyst, agates, petrified wood & chalcedony are all varieties of quartz or silica & form from hydrothermal fluids in volcanic environments

Turquoise (means  “brought  through  Turkey”)

• Derived from low temp. fluids by the weathering of pre-existing sedimentary phosphate deposits

• Mined for 4,000 years• Found in Persia (Iran, country of the “pure”race), Arizona, Mexico

• Beware of imitations!• $ 2 to $40 per carat

Turquoise

Aztec God of Fire

Dome of the Rock, Jerusalem

PEGMATITES

• The  source  of  the  world’s  finest  tourmaline,  beryl & topaz and the main source of more than 70 gemstones

• Host to an extreme diverse mixture of exotic minerals & the sole source of very rare minerals

• Combination of gigantic crystals & extreme enrichment of rare elements

Baffin Island, Nunavut: white lines are pegmatites

Aquamarine

• Important source of Be, Nb, Ta, Sn, Li, Rb, Cs & Ga• Most  of  the  world’s  renowned  pegmatites are

now mined mainly for gems• Pegmatites come in many sizes & shapes• Their internal structure can be simple (all crystals

same size), zoned (layers of many sizes of crystals), while the complex have superimposed areas of later alteration with other minerals

• Complex pegmatites have pockets or vugslined with beautiful gem crystals

• The main ingredients of most pegmatites are quartz, feldspar and mica

• Gems may form layers in between the above or as pockets

Fluids rich in

• H2O, B, Li, F, P, CO2• Rare elements such as Cs, Ta, Nb, REE, Zr, U,

Sn

“Gem  pockets”

Colorado

Tourmaline

• Great variety of colors and compositions• A boron silicate with many other metals• Found worldwide• A large cut gem of 191 carats, flawless oval

from Brazil was presented in Montreal in 2009 for selling purposes

• Another from Mozambique sells for $ 5,000 per carat

This  picture  can’t  be  copied!

Topaz

Topaz

• A silicate with aluminum and fluorine• Name from name of a small island in the Red

Sea (Topazos) where a yellow stone was mined

• It may not be the mineral we call topaz today• Price per carat: from $10 to $700

Colorless variety

Yellow variety

Beryl

• Price per carat: $30 to $200• A beryllium silicate• Name  means  “precious  blue  –green color –of-

sea-water  stone”

Aquamarine: blue variety of beryl

• Means  “water  of  the  sea”• Color can change or be improved by

irradiation

Emerald: green variety of beryl

• Symbol of immortality for 4000 years• Cleopatra’s  mine  was  thought  to  be  the  only  

source• Now, it is possible to track gem to it source,

country and individual mine!• They have very specific oxygen isotope levels,

reflecting composition & temp. of the fluids that deposited them as well as the rocks that its elements flowed through

“The  Secret  Life  of  Emeralds”

• To measure the isotopes, bombard gem with a beam of charged caesium atoms

• Those from the Holy Crown in France came from the Swat-Mingora distruct in Pakistan, a big surprise to the investigators

• Another surprise was emeralds in India came from Columbia!

• Columbia emeralds are unique, rich in color, clarity and bigger crystals

• Green color due to trace amounts of chromium and some vanadium

• Relatively rare stone, hence it is very pricy• Price per carat: from $20 to $500 or much

higher• Hardness 7.5 to 8 (one of the hardest

substances)

Canada’s  emeralds

• Yukon: found in pegmatites, are Vanadium-rich, discovered in 1998

Yukon’s  emeralds

Dryden, Ont. emeralds

3. Metamorphic deposits

• Garnet, lapis, zoisite, ruby & emerald• Most rubies in high-grade meta. rocks like

gneiss & marble –Burma the largest producer• Most  of  world’s  emeralds mined in

carbonaceous schists in Colombia• Lilac/purple variety of cordierite (iolite) in

gneiss (in Manitoba)

Jade (green due to Fe)

• World’s  toughest  stone• Mixture of two minerals: jadeite & nephrite• Lillooet  area  has  the  world’s  biggest  reserves• Prized for its toughness & its almost mirror

finish when polished• When hit with a hammer, it produces tiny,

feathery cracks, unique for jade

• Jade is an aggregate of two minerals, jadeite (pyroxene) & nephrite (amphibole)

• Very tough, the two minerals are strongly interlocking

• Jadeite is glassy, bright & crystalline. Found mostly in Burma

• Nephrite is what the Chinese have venerated for millenia. BC has reserves to meet world demand for several hundred years

Unworked

Display at Jade City, BC

Bringing more pieces

In China jade worth more than gold

Prospecting for jade in Jade River, China

Garnet

• Six varieties with different names• Differences in chemical composition and color• Used as gemstones and abrasives (sandpaper)

since the Bronze Age• Also, sand blasting and wood finishing• Abundant supply in mineral sands in India &

Australia

Deep red color

Lapis  Lazuli  “heaven  stone”• Means  “stone  of  the  blue”• In  ancient  times  known  as  “sapphirus”,  which  

today we use for the blue corundum (sapphire) • One mine in Afghanistan, 7,000 years old (Sar-e-

Sang) in the region called Badhakshan (name from ancient Greek Balaskia, which means the Vault). Treacherous terrain of precipitous mountains

• Flourishing trade due to its unusual color• Color due to sulfur-rich mineral, also contains

grains of pyrite & white marble

4. Sedimentary deposits

• The most valuable is precious opal• Some deposits are complete replacement of

fossil shells, dinosaurs, belemnites, etc• Others are as replacement layers within

sedimentary rocks, but discontinuous & as small pods a few cm thick

Opal, Australia

Coober Pedy, Australia

Opalized bivalve (seashell)

250,000 mine shafts!

“Opal  capital  of  the  world”

“dugout”

Coober Pedy

• In the middle of the desert• To avoid extreme heat of the summer people

dug underground houses. They remain at constant temperature. Cost as much to build as house on surface. You can do mining at the same time

• Prospectors given 15.3 m2 parcels of land to explore. No large-scale mining allowed

5. Placer deposits

• Because of their toughness and resistance to erosion, gemstones are relatively abundant as placer deposits along rivers

• Diamonds, sapphires, zircons, topaz, rubies, garnets, agates & petrified wood

Mineral sands: everyone, every day are using them

• Paint on the wall, color in clothing, printing inks, ceramics on the wall, TVs, computers, make-up, medicines, etc

• Ilmenite• Zircon• Rutile• monazite

Where?

• India, Australia, Brazil• All these minerals are heavier than normal

rocks, so they tend to separate• Important source of REEs, Ti, Th, Zr and gems

like diamond, sapphire & garnet• Low-grade operations. Only in some countries,

there is rehabilitation after mining (Australia, Namibia, Chile)

Ilmenite (TiO2)

• Weakly magnetic (contains some Fe)• Difficult to distinguish from magnetite, but it

has a white rim of leucoxene• Main source of Ti metal• Main Ti mineral in the Cross Lake deposit• The Vanadium content of the Cross Lake is not

good for processing• Its powder is white

Black ilmenite with leucoxene rim

Ilmenite (titanium)

• Refined as TiO2 pigment, one of the whitest substances on Earth. The unique reflective and opaque characteristics of Ti dioxide form the basis for most high quality coloring agents, giving paints and dyes a brilliance rarely seen before the 20th century

• Titanium is highly resistant to corrosion in sea water and has the highest strength-to-density ratio of all metals

Zircon

• Used in ceramics, refractories, chemical processing and insulation, zircon is one of the toughest materials in existence. Improved technology is creating a demand for zircon as a valuable component of futuristic engines, bearings, computer disc drives and cutting equipment

• Zircon silicate in composition, but it may contain REEs, U, Th

• To produce zirconium dioxide, one of the most refractory materials known

• Zircon’s  main  use  as  a  opacifier, in ceramics• Due to inertness, durability & hardness, it

persists weathering and remains in sands• Valuable mineral for radiometric dating due to

small amount of U & Th that it contains

Can’t  copy!

Rutile

• Rich in titanium dioxide, rutile is the feedstock for the new generation of pollution-free pigment plants. Raw material for light durable titaniummetal, rutile is essential to the aerospace industries. Non-reactive Ti is the most successful “human  space  parts”  material  for  modern  surgery

• Has special optical properties (very high refractive index), so used in optics

• Used as sunscreens to protect against UV

• Composed of TiO2• Most common natural form of TiO2• May also contain iron, niobium & tantalum

Monazite (= to be solitary)

• Separated into rare earths, monazite provides elements vital to some of the most exciting developments in modern technology. Computers, medical technology and electronic industries are all dependent on rare earths

• A source of Thorium• May also contain He- extracted by heating it• Can be radioactive – used for dating rocks

Ce, La, Th, Nd, Y phosphate

Old monazite mine in North Carolina

Videos on gems

• 1.  “Stones  of  Seduction”:  rubies  &  sapphires• Color of rubies due to chromium• Color of sapphires due to iron & titanium• “Crown  Jewels”  in  the  Tower  of  London,  

over 350 years old preserved in very clean air• Found in Sri Lanka in alluvial deposits (rivers)

2. (video) Topaz

• Place for irradiation in Vancouver• turns them into blue color• yellow  “Imperial  Topaz”  from  Brazil  is  very  rare• A Gemologist needs to do tests to prove it is:

take a picture, weigh & measure it, look under the microscope, use a refractimeter to test its refractive index & its specific gravity

• Value at $ 7,700

3.(video)Colombian Emeralds: “value  is  in  the  color”

• Formed with pyrite, so they contain no iron. That makes them glow more & fluoresce in the sun

• 1,000 year old Muzo mine still using old mining methods with many poor people sifting mud in the river below hoping to get rich

• Emerald Trading Centre in Bogota• People buy there & bring to sell in the

USA/Canada Up to $ 9,000 per carat

4.(video) Amber

• Poland & Kaliningrad, Russia• Amber floats because it is lighter than a rock• For jewelry & fossil inclusions• Russians    also  make  “pressed  amber”  by  

melting small pieces• Many imitations

EXPERIMENT

• With samples of sand• Remember: it is the rivers that break down

rock to form sand. So, rivers act like the “crushers”  of  the  Limestone plant

Small  collection  of  “sands”:  7  samples

• 2 from shores of lakes• 1 from wind-blown shore of lake• 1 from an esker• 1  from  Michelle’s  sand  deposit  – river/esker?• 1 from volcanic island with black sand• 1 unknown purple sand (Manitoba)

All tested with a magnet

• Magnet will pick magnetite/pyrrhotite, but may also pick ilmenite

• The amount of magnetic material will be an indication  of  how  much  “mineral  sands”  we  may have in the samples

Results

• 2 shores of lake: NONE• 1 wind-blown from shore: NONE• 1 esker : some• 1  Michelle’s  :  some• 1 volcanic island: a great deal• 1 unknown: lots

Conclusion

• Lake shore sand may have been separated, with  “heavies”  underneath  the  “lights”

• Esker and river sand may be sources of “mineral  sands”

• Anyone dredging a river bed – to avoid/reduce risk from flooding – can pick up some credits

Other gems in Canada• Sapphire• Ruby• Beryl: emerald & aquamarine• Topaz• Tourmaline• Spinel• Cordierite• Zircon• Peridot

• Garnet – almandine• Garnet – pyrope• Garnet – spessartine• Quartz – amethyst• Quartz - citrine

Corundum

• Nunavut• Ontario• BC• Newfoundland

Beryl (emerald)

• Ontario: Dryden area• NWT• Yukon• Nunavut

Beryl (Aquamarine)

• BC• Yukon• Ontario• Quebec• Nova Scotia

Topaz

• BC• Yukon

Tourmaline

• NWT• Quebec• Nunavut• Ontario

Spinel

• Ontario• Nunavut

Cordierite (Iolite)

• BC• Ontario• Manitoba• NWT• Nunavut

Cordierite

• Northern Manitoba: blue-violet with strong pleochroism

• Many applications as insulator, resistor, etc

Zircon

• Ontario

Peridot

• BC• Yukon• NWT• Ontario

Garnet: many kinds

• Ontario• Quebec• NWT• Yukon• Nunavut• BC

Manitoba minerals

• Staurolite (cross-shaped)• Cordierite • Gypsum rosettes in the soil, esp. in the

Floodway• Lepidolite (Li)• Pollucite (Cs)

A trip to the Lapis mines

Balaskia, Afghanistan

Follow the Korcha river

Man  wearing  “kausia”,  ancient Greek hat

Florida restaurant

At the end of the Korcha river

Remains of ancient Greek city, Afghanistan/Tajikistan border, Korcha/ Amur rivers