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Variety · Silicate

Andesine

(Ca,Na)(Al,Si)₄O₈

Intermediate plagioclase; red 'andesine' gems are often treated feldspar.

Hardness6–6.5
Crystal systemTriclinic
ClassSilicate
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Andesine specimen

Andesine, mineral mix from Albite and Anorthite Dimensions: 6 cm x 5 cm x 5 cm Locality: Montpelier Mine (Bowe Farm Prospect; Feldspar Corporation Quarry), Mont — Photo: Mike Dennis · Public domain

Andesine

A mid-range plagioclase feldspar, about halfway between sodium-rich albite and calcium-rich anorthite.

Intro adapted from Wikipedia (CC BY-SA).

Andesine is a mineral variety of Anorthite, with the chemical formula (Ca,Na)(Al,Si)₄O₈.

It crystallizes in the triclinic crystal system.

Key properties: Mohs hardness 6–6.5; specific gravity 2.67; typically white or gray or red; refractive index 1.553; optically biaxial.

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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. Browse more A minerals or help write this entry.