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orthoclase Line breaks: ortho|clase
Pronunciation: /ˈɔːθəkleɪz/

Definition of orthoclase in English:


[mass noun]
A common rock-forming mineral occurring typically as white or pink crystals. It is a potassium-rich alkali feldspar and is used in ceramics and glass-making.
Example sentences
  • Feldspars are added as orthoclase in order to reduce the devitrification of the glass.
  • Of these, alkali feldspar, particularly orthoclase, is the most common.
  • Associated minerals are white orthoclase, milky quartz, and muscovite.


Mid 19th century: from ortho- 'straight' + Greek klasis 'breaking' (because of the characteristic two cleavages at right angles).

Definition of orthoclase in:
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