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Pengenalan Mineral

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Pengertian Mineral

Mineral adalah bahan bentukan alam yang mempunyai komposisi kimia tertentu, padaumumnya anorganik, dan kristalin padat

"A mineral is an element or chemical compound that is normally crystalline and that hasbeen formed as a result of geological processes" (Nickel, E. H., 1995).

"Minerals are naturally-occurring inorganic substances with a definite and predictablechemical composition and physical properties." (O' Donoghue, 1990).

"A mineral is a naturally occurring homogeneous solid, inorganically formed, with adefinite chemical composition and an ordered atomic arrangement" (Mason, et al, 1968).

"These... minerals ...can be distinguished from one another by individual characteristicsthat arise directly from the kinds of atoms they contain and the arrangements these atomsmake inside them" (Sinkankas, 1966).

"A mineral is a body produced by the processes of inorganic nature, having usually adefinite chemical composition and, if formed under favorable conditions, a certaincharacteristic atomic structure which is expressed in its crystalline form and otherphysical properties" (Dana & Ford, 1932).

"Every distinct chemical compound occurring in inorganic nature, having a definitemolecular structure or system of crystallization and well-defined physical properties,constitutes a mineral species" (Brush & Penfield, 1898).

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Bagaimana orang mempelajari mineral

Berdasarkan sifat fisik

Berdasarkan komposisi kimia

Berdasarkan sifat optik (dengan bantuanmikroskop polarisasi dan pantul)

Berdasarkan struktur ikatan kimia (x-ray

diffraction)

Bagaimana cara terbentuknya (genesanya,

terkait dengan pembentukan batuan)

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Sifat Fisik Mineral

Warna (color)

Cerat (streak)

Kilap (luster)

Kekerasan (hardness)

Belahan (cleavage) Pecahan (fracture)

Bentuk kristal (crystal form)

Masa jenis dan kerapatan (specific gravityand unit weight)

Daya hantar panas, listrik (heat & electrical conductivity)

Indeks bias

Daya simpan cahaya (fluorescence)

Kemagnitan (magnetism)

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Cerat (Streak)

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Kilap (Luster)

Kemampuan permukaan mineral mereflesikan cahaya

macamnya- Metallic (logam)

- Vitreous (kaca)

- Resinous (resin)

- Greasy (lemak)

- Pearly (mutiara)

- Silky (sutera)- Adamantin (intan)

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Kilap (Luster)

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Kekerasan (Hardness)

Kekerasan adalah ketahanan mineral terhadap goresan

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Cleavage

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Cleavage

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Fracture

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Mineral Form

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Mineral Form

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Mineral Form

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Crystal Form

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Crystal Form

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Mineral form

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Chemical

Bounding

andCleavage

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Chemical

Composition

/ Classification

Old Dana Classification New Dana Classification

I Native Elements Class 1

II Sulfides Classes 2& 3

III Oxides and Hydroxides Classes 4, 5, 6, 7, & 8

IV Halides Classes 9, 10, 11, & 12

V Carbonates, Nitrates,

Borates

Classes (13, 14, 15, 16a, 16b, 17)Carbonates

(18, 19, 20)Nitrates

(21, 22, 23)Iodates

(24, 25, 26, &27)Borates

VI Sulfates, Chromates,

Molybdates

Classes (28, 29, 30, 31, 32)Sulfates

(33)Selenates & Tellurates

(34)Selenites - Tellurites - Sulfites

(35, & 36)Chromates

VII Phosphates, Arsenates,

Vanadates

Classes (37, 38, 39, 40, 41, 42, 43)Phosphates

(44, 45, 46)Antinomates

(47)Vanadates et. al.

(48, & 49)Molybdates & Tungstates

IX Organic Minerals Class 50

VIII Silicates

Nesosilicates Classes 51, 52, 53, & 54

Sorosilicates Classes 55, 56, 57, & 58

Cyclosilicates Classes 59, 60, 61, 62, 63, & 64

Inosilicates Classes 65, 66, 67, 68, 69, & 70

Phyllosilicates Classes 71, 72, 73, & 74

Tektosilicates Classes 75, 76, & 77

Not Classified Silicates Class 78

Complete List(860 Kb) Classes 1-78

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Sifat Optik Mineral

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Sifat Optik Mineral

Principle of petrographicmicroscope

Mineral on petrographicmicroscope

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X-ray analysis

Powder X-ray Diffraction (XRD)is one of the primary techniquesused by mineralogists and solid state chemists to examine thephysico-chemical make-up of unknown solids. This data isrepresented in a collection of single-phase X-ray powder diffraction

patterns for the three most intense D values in the form of tables ofinterplanar spacings (D), relative intensities (I/Io), hkl plane, mineralname and chemical formulas.

The XRD techniquetakes a sample of the material and places apowdered sample in a holder, then the sample is illuminated with x-rays of a fixed wave-length and the intensity of the reflectedradiation is recorded using a goniometer. This data is then analyzedfor the reflection angle to calculate the inter-atomic spacing (D valuein Angstrom units - 10-8 cm). The intensity(I) is measured todiscriminate(using I ratios) the various D spacings and the resultsare compared to this table to identify possible matches.

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Contoh Hasil X-ray