| adularia |
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noun (plural: adularias)
- A variety of orthoclase feldspar found as colorless to white prismatic crystals in cavities in metamorphic rocks. Some specimens reflect a bluish sheen along crystal faces. This phenomenon is called adularescence, and adularia with this property is called moonstone. (See sanidine).
- Chemical composition: Potassium aluminum silicate, <math>KAlSi?_3O_8</math>
- Physical properties:
Moh's Hardness: 6.0
Specific gravity: 2.6
Color: white, colorless
Luster: glassy
Fracture: conchoidal
Habit: prismatic.
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| albite |
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noun (plural: albites)
- (mineralogy) A plagioclase feldspar, the first member of the Albite-Anorthite solid solution series. Primarily a mineral of plutonic rocks, also found in pegmatites. When Albite substitutes for a potassium feldspar in granite, the rock is called quartz monzonite.
- Chemical composition: Sodium aluminum silicate, <math>NaAlSi?_3O_8</math>
- Physical properties:
Moh's Hardness: 6.0
Specific gravity: 2.63
Color: white, sometimes with a bluish cast
Luster: glassy
Fracture: conchoidal
Cleavage: two good at about 94º to each other
- Habit: Triclinic - pinacoidal. Usually twinned and striated. The striations are visible to the naked eye, and are characteristic of plagioclase feldspars in general and Albite in particular.
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| allomorph |
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noun - (chemistry) any of the different crystalline forms of a substance
- (linguistics) any of the different phonological representations of a morpheme
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| amalgam |
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noun (pl=amalgams)
- A combination of different things
- An alloy containing mercury
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| amianthus |
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noun
- a type of asbestos with long, soft, thin fibers
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| amphibole |
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noun
- A large group of structurally similar hydrated double silicate minerals, containing various combinations of sodium, calcium, magnesium, iron, and aluminium/aluminum
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| anatase |
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noun
- a blue or brown mineral, a form of titanium dioxide, used as a pigment
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| andesine |
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noun
- (mineralogy) sodium calcium aluminum silicate, (<math>Na_xCa_xAlSi_3O_8</math>), a plagioclase feldspar, the third member of the albite-anorthite solid solution series. Found in fine-grained andesite lavas; crystals are rarely seen.
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| anhydrite |
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noun - (mineralogy) a saline evaporite consisting of anhydrous calcium sulphate
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| anisometric |
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adjective
- Not isometric or symmetrical.
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| anorthite |
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noun (plural: anorthites)
- (mineralogy) A plagioclase feldspar, the final member of the Albite-Anorthite solid solution series. Anorthite is very rare on Earth, but abundant in moon rocks. This is because Anorthite weathers rapidly to clay minerals under atmospheric conditions. Good crystals have been found in lava-digested limestone blocks erupted from Mount Vesuvius.
- Chemical composition: Calcium aluminum silicate, <math>CaAlSi?_3O_8</math>
- Physical properties:
Moh's Hardness: 6.0
Specific gravity: 2.76
Color: Shades of gray, often with a blue, purple, or green cast
Luster: glassy
Fracture: conchoidal
Cleavage: two good at about 94º to each other
- Habit: Triclinic - pinacoidal. Crystals are well developed, forming massive clumps, and are both twinned and striated.
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| apatite |
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noun
- (mineralogy) a calcium fluoride phosphate of variable composition used in the manufacture of fertilizer
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| aragonite |
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noun - (mineralogy) a saline evaporite consisting of anhydrous calcium carbonate; it is dimorphous with calcite
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| argentite |
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noun (uncountable)
- (mineralogy) silver sulphide, (<math>Ag_2S</math>), a primary ore of silver, in cubic or hexoctahedral crystals.
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| arsenic |
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noun
- A nonmetallic chemical element (symbol As) with an atomic number of 33.
- arsenic trioxide, Arsenic trioxide.
adjective
- Of, or containing arsenic with a valence of 5.
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| asbestos |
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noun
- Either of several fibrous mineral forms of magnesium silicate, used for fireproofing, electrical insulation, building materials, brake linings, and chemical filters; The small fibres can cause cancer when lodged in the lungs
adjective
- Of, or relating to asbestos.
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| augite |
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noun - A variety of pyroxene, usually of a black or dark green color, occurring in igneous rocks, such as basalt.
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| auriferous |
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adjective
- containing or producing gold; gold-bearing
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| aventurine |
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noun
- A kind of glass, containing gold-colored spangles. It was produced in the first place by the accidental (par aventure) dropping of some brass filings into a pot of melted glass.
- (mineralogy) A variety of translucent quartz, spangled throughout with scales of yellow mica.
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| axinite |
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noun
- A borosilicate of aluminum, iron, and lime, commonly found in glassy, brown crystals with acute edges.
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| azurite |
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noun - (mineralogy) A blue vitreous mineral; a basic copper carbonate
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