orthoclase
9.9
A common mineral often white or pink found in granite and other hard rocks
- noun
- /ˈɔrθəˌkleɪs/
- Specialized
:
ortoclasa
- Geologists identify orthoclase by its distinct monoclinic crystal structure and light color.
Examples
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In many igneous rocks, orthoclase occurs alongside quartz and mica as a key mineral.
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The mineral orthoclase is easily identified by its light color and monoclinic crystal structure.
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The range is as follows: talc 1; gypsum 2; calcite 3; fluorite 4; apatite 5; orthoclase 6; quartz 7; topaz 8; corundum 9; and diamond 10.
Academic text (1993)
How Hard
Surface Forms
orthoclase singular
orthoclases plural
Etymology
The word orthoclase comes from Greek words orthos 'straight' and klasis 'breaking', so its name means 'straight break'. That's a helpful image because this feldspar often splits along straight planes, which is why geologists call the mineral orthoclase.