How can you identify Glaucophane?

Compare several properties rather than relying on colour alone. This entry records colour: Blue to lavender-blue; lustre: Vitreous; streak: Grayish blue; Mohs hardness: 6-6.5; cleavage: Good in two directions at 56°; crystal system: Monoclinic; transparency: Translucent. Confirm an important identification with additional field tests or qualified laboratory work.

What is Glaucophane commonly confused with?

Glaucophane may be confused with Riebeckite, Lazulite, Kyanite. Compare multiple diagnostic properties because colour and surface appearance can overlap.

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Glaucophane identification and geology

Blue sodic amphibole characteristic of high-pressure, low-temperature metamorphism in subduction zones. Gives blueschist its name. Color: Blue to lavender-blue. Luster: Vitreous. Streak: Grayish blue. Cleavage: Good in two directions at 56°. Hardness: 6-6.5. Transparency: Translucent. Crystal system: Monoclinic. Chemical formula: Na₂ Mg,Fe ₃Al₂Si₈O₂₂ OH ₂. Specific gravity: 3.0-3.2. Formation: Forms under high-pressure, low-temperature conditions in subduction zone metamorphism. Common geological settings: California, Japan, Turkey, Greece; diagnostic mineral of blueschist facies. Common look-alikes and related entries: Riebeckite, Lazulite, Kyanite.

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Riebeckite
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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: 2026-03-30T14:36:46.220359+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.

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Common questions

What is Glaucophane?: Blue sodic amphibole characteristic of high-pressure, low-temperature metamorphism in subduction zones. Gives blueschist its name.
How can you identify Glaucophane?: Compare several properties rather than relying on colour alone. This entry records colour: Blue to lavender-blue; lustre: Vitreous; streak: Grayish blue; Mohs hardness: 6-6.5; cleavage: Good in two directions at 56°; crystal system: Monoclinic; transparency: Translucent. Confirm an important identification with additional field tests or qualified laboratory work.
How does Glaucophane form?: Forms under high-pressure, low-temperature conditions in subduction zone metamorphism.
Where is Glaucophane commonly found?: California, Japan, Turkey, Greece; diagnostic mineral of blueschist facies.
What is Glaucophane commonly confused with?: Glaucophane may be confused with Riebeckite, Lazulite, Kyanite. Compare multiple diagnostic properties because colour and surface appearance can overlap.

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Glaucophane identification and geology

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Sources, scope & corrections

Common questions