M MineralystRock & Mineral Guide
Gemstone

Moonstone

Moonstone — reference photo

Moonstone is a gemstone with the chemical formula KAlSi3O8. It has a Mohs hardness of 6 - 6.5 and vitreous to pearly luster.

Moonstone properties

TypeGemstone
Chemical formulaKAlSi3O8
Mohs hardness6 - 6.5
LusterVitreous to pearly
Typical colorsColorless, gray, blue, peach, green
FormationIgneous, formed through the slow cooling of molten rock
Rarity6 / 10

Mohs hardness 6–6.5 — fairly hard

1 · Talc5 · Apatite10 · Diamond
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