Magnesium-rich mica that forms yellowish-brown flexible sheets. Important in ultramafic and carbonate-hosted metamorphic rocks. Color: Yellow-brown, reddish-brown. Luster: Vitreous to pearly. Streak: White. Cleavage: Perfect basal cleavage. Hardness: 2.5-3. Transparency: Transparent to translucent. Crystal system: Monoclinic. Chemical formula: KMg₃ AlSi₃O₁₀ OH ₂. Specific gravity: 2.78-2.85. Formation: Forms in metamorphosed magnesian limestones and in ultramafic igneous rocks like kimberlites. Common geological settings: Canada, Madagascar, Sri Lanka, Finland; found in marbles and kimberlites. Common look-alikes and related entries: Biotite, Muscovite, Vermiculite.
Gold look-alikes — Place this specimen in a broader field-identification workflow.
Sources, scope & corrections
These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
Editorial owner
GeoMiner
Last updated
2026-03-30T14:36:45.266309+00:00
Review status
Published; not independently peer-reviewed
IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.
Magnesium-rich mica that forms yellowish-brown flexible sheets. Important in ultramafic and carbonate-hosted metamorphic rocks.
How can you identify Phlogopite?
Compare several properties rather than relying on colour alone. This entry records colour: Yellow-brown, reddish-brown; lustre: Vitreous to pearly; streak: White; Mohs hardness: 2.5-3; cleavage: Perfect basal cleavage; crystal system: Monoclinic; transparency: Transparent to translucent. Confirm an important identification with additional field tests or qualified laboratory work.
How does Phlogopite form?
Forms in metamorphosed magnesian limestones and in ultramafic igneous rocks like kimberlites.
Where is Phlogopite commonly found?
Canada, Madagascar, Sri Lanka, Finland; found in marbles and kimberlites.
What is Phlogopite commonly confused with?
Phlogopite may be confused with Biotite, Muscovite, Vermiculite. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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