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Orthoclase

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Ruby, Orthoclase, and Emerald

1:36

All you want to know about Orthoclase Stone

1:17

Potassium feldspar (orthoclase)

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Orthoclase: The mineral Orthoclase information and pictures

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Orthoclase under microscope

Orthoclase, or orthoclase feldspar (endmember formula KAlSi3O8), is an important tectosilicate mineral which forms igneous rock. The name is from the Ancient Greek for "straight fracture," because its two cleavage planes are at right angles to each other. It is a type of potassium feldspar, also known as K-feldspar. The gem known as moonstone (see below) is largely composed of orthoclase.
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    • Formation and subtypes 

    • Uses