Muscovite (KAl₂(AlSi₃O₁₀)(OH)₂) is the most common mica species and a defining sheet silicate. Its name comes from “Muscovy glass” — large transparent Muscovite plates from Russia historically used as windowpanes. Muscovite forms in granitic pegmatites, schists, and gneisses, where it grows as flexible elastic books reaching meter-scale dimensions.
Key Facts
- Mohs hardness 2–2.5.
- Monoclinic phyllosilicate; perfect basal cleavage produces flexible elastic sheets.
- Pseudohexagonal tabular crystal habit.
- Major rock-forming mineral in granites, pegmatites, and metamorphic schists.
- Used industrially as electrical insulator and filler.
Notable Localities
Madras (India) and Brazil supply industrial-grade Muscovite books. Galileia (Brazil) yields meter-scale collector specimens. Russia’s Karelia provided the historical “Muscovy glass.”
Found at these Localities
- Swiss Alps (Alpine-Cleft Province) (瑞士阿尔卑斯高山裂隙矿物产地)
- Eastern Brazilian Pegmatite Province (巴西东部伟晶岩省)
- Trimouns Talc Mine (特里穆滑石矿(法国))
- Ural Emerald Mines (乌拉尔祖母绿矿)
- Panasqueira (帕纳斯凯拉钨矿)
- Volyn (Volodarsk-Volynskii) (沃伦伟晶岩区)
- Skardu / Shigar Valley (斯卡都/希加尔峡谷)
- Madagascar Pegmatites (Sahatany / Antsirabe) (马达加斯加伟晶岩区)
- Linópolis Pegmatites (利诺波利斯伟晶岩区)
- Ouro Preto Region (欧鲁普雷图矿区)
- Dachang Tin-Polymetallic Field (大厂锡多金属矿田)
- Maharashtra Deccan Traprock Zeolites (马哈拉施特拉德干玄武岩沸石产地)
