Labradorite
From Fresh Dictionary
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English
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Etymology
Named for the type locality in Labrador.
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Noun
labradorite (plural: labradorites)
- (mineralogy) A plagioclase feldspar, the fourth member of the Albite-Anorthite solid solution series. Often very coarsely crystalline, it is used as a decorative stone for carvings and building façades. Crystal surfaces often show a bluish reflection called "Schiller", which resembles the reflections from a butterfly's wing.
- Chemical composition: Calcium sodium aluminum silicate, <math>Ca_xNa_xAlSi_3O_8</math>
- Physical properties:
- Moh's Hardness: 6.0
- Specific gravity: 2.71
- Color: Usually bluish-gray to dark gray
- Luster: glassy
- Fracture: conchoidal
- Cleavage: two good at about 94º to each other
- Habit: Triclinic - pinacoidal. Crystals are common and usually striated.
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Related terms
- See Rock, Feldspar, Plagioclase