Phlogopite (KMg₃(AlSi₃O₁₀)(OH,F)₂) is the magnesium end-member of the biotite series and the distinctive bronze-yellow to brown mica. It forms in metamorphosed dolomitic limestones and ultramafic rocks, often as large transparent honey-colored books. Mg-rich phlogopite is a refractory mineral that survives in mantle xenoliths and kimberlite pipes.
Key Facts
- Mohs hardness 2–2.5.
- Monoclinic phyllosilicate; perfect basal cleavage.
- Bronze-yellow to brown from Fe³⁺ trace content; pure Mg phlogopite is pale gold.
- Refractory mica stable in mantle environments — kimberlite indicator alongside forsterite.
- Forms in metamorphosed dolomites and ultramafic intrusions.
Notable Localities
Burgess (Ontario, Canada) and Madagascar yield large transparent honey-brown books. Phalaborwa (South Africa) hosts industrial phlogopite. Mongolia supplies high-quality collector material.
Found at these Localities
- Italian Volcanic Province (Vesuvius / Lipari / Etna) (意大利火山矿物产地)
- Kola Peninsula Alkaline Complexes (科拉半岛碱性杂岩)
- Ural Emerald Mines (乌拉尔祖母绿矿)
- Mogok Stone Tract (抹谷宝石产地)
