“Moonstone” (iridescent peristerite-oligoclase feldspar) from the Precambrian of Russia. (10.9 cm across at its widest) The term “moonstone” has been used to re — Photo: James St. John · CC BY 2.0
Oligoclase
Also known as: Sunstone.
The plagioclase feldspar midway between albite and anorthite — a common white-to-gray rock former.
Intro adapted from Wikipedia (CC BY-SA).
Oligoclase is a mineral variety of Albite, with the chemical formula (Ca,Na)(Al,Si)₄O₈.
It crystallizes in the triclinic crystal system.
Key properties: Mohs hardness 6–6.5; typically white or gray or yellow.
Collections: Collector Favorites.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data and a Wikipedia introduction — a full written entry hasn’t been published yet.
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