Staurolite is a fascinating metamorphic mineral famously known for its penetration twins that form cross-like shapes, often called 'fairy crosses'. It is a key indicator mineral for medium-grade metamorphic rocks and is typically found embedded in mica schist, standing out as dark, prismatic crystals against a lighter matrix.
Is this staurolite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch staurolite with a known reference. Staurolite sits at Mohs 7-7.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Staurolite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Staurolite typically shows a vitreous to resinous luster.
- 4Match the color rangeCompare against the expected color range: reddish-brown, brown, brownish-black, yellowish-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic, often cruciform penetration twins.
Often confused with
Staurolite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to resinous on Staurolite and vitreous on Andalusite.
How to tell apart: Luster reads vitreous to resinous on Staurolite and vitreous on Kyanite.
How to tell apart: Luster reads vitreous to resinous on Staurolite and vitreous on Garnet.
Often found alongside staurolite
Minerals reported to co-occur with staurolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₂Al₉Si₄O₂₂(OH)₂
- Mohs hardness
- 7-7.5
- Density
- 3.7-3.8 g/cm³
- Streak
- White
- Luster
- Vitreous to Resinous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic, Often Cruciform Penetration Twins
- Cleavage
- Distinct On {010}
- Rarity
- Common
- Uses
- Collector, Educational
- Host rock
- Metamorphic Schists and Gneisses
- Typical price
- $5-50 for typical specimens, higher for perfect fairy cross twins
Where rockhounds find staurolite
59 mapped spotsClassic worldwide localities
- Taos County, New Mexico, USA
- Fannin County, Georgia, USA
- Brittany, France
- Pizzo Forno, Switzerland
- Minas Gerais, Brazil
U.S. states with staurolite
Each link opens a state-specific list of mapped rockhounding spots that produce staurolite.
Field-hunting tip
Look in metamorphic schists and gneisses country — that is the host setting where staurolite typically forms. If you start seeing kyanite, garnet, mica in float, you are in the right ground. Field specimens usually show a prismatic, often cruciform penetration twins habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in North Carolina, Georgia, New Hampshire — start trip planning there.
Common questions
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Find staurolite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
