Metamorphic index mineral famous for its cruciform penetration twins fairy crosses . Indicates medium-grade metamorphism. Color: Dark brown, reddish-brown, yellowish-brown. Luster: Vitreous to resinous. Streak: White to grayish. Cleavage: Poor. Hardness: 7-7.5. Transparency: Translucent to opaque. Crystal system: Monoclinic. Chemical formula: Fe₂Al₉O₆ SiO₄ ₄ O,OH ₂. Specific gravity: 3.7-3.8. Formation: Forms during medium-grade regional metamorphism of pelitic rocks in the staurolite zone. Common geological settings: Virginia fairy crosses , Switzerland, Russia, Brazil; found in mica schists and gneisses. Common look-alikes and related entries: Andalusite, Chiastolite, Tourmaline.
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.
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Last updated
2026-03-30T14:36:53.906134+00:00
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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.
Metamorphic index mineral famous for its cruciform penetration twins fairy crosses . Indicates medium-grade metamorphism.
How can you identify Staurolite?
Compare several properties rather than relying on colour alone. This entry records colour: Dark brown, reddish-brown, yellowish-brown; lustre: Vitreous to resinous; streak: White to grayish; Mohs hardness: 7-7.5; cleavage: Poor; crystal system: Monoclinic; transparency: Translucent to opaque. Confirm an important identification with additional field tests or qualified laboratory work.
How does Staurolite form?
Forms during medium-grade regional metamorphism of pelitic rocks in the staurolite zone.
Where is Staurolite commonly found?
Virginia fairy crosses , Switzerland, Russia, Brazil; found in mica schists and gneisses.
What is Staurolite commonly confused with?
Staurolite may be confused with Andalusite, Chiastolite, Tourmaline. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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