Staurolite Schist is a medium-grade metamorphic rock characterized by the presence of cruciform or prismatic staurolite crystals embedded within a mica-rich matrix. It is highly sought after by collectors for the 'fairy cross' habit of the staurolite porphyroblasts, which often stand out clearly against the schistose background. It is typically found in regional metamorphic terranes formed under moderate temperatures and pressures.
Is this staurolite schist?
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 schist with a known reference. Staurolite Schist sits at Mohs 3.5-7, softer than the next harder reference, harder than the previous one.
- 2Read the textureLook at a fresh break with a hand lens. Texture: Schistose, often with staurolite porphyroblasts twinned in a cross shape. Grain size: Medium-grained (grains 0.25 to 2 mm).
- 3Pick out the mineralsComposition: Mica-rich schist with staurolite, often with almandine garnet, kyanite, biotite or sillimanite. Identify the two or three most abundant grains.
- 4Read the lusterHold the specimen under a strong light. Luster: pearly to dull.
- 5Match the color rangeCompare against the expected color range: dark brown, gray, brownish-black.
Often found alongside staurolite schist
Minerals reported to co-occur with staurolite schist. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 3.5-7
- Density
- 2.7-3.0 g/cm³
- Luster
- Pearly to dull
- Transparency
- Opaque
- Rarity
- Common
- Uses
- Collector, Educational
- Host rock
- metamorphic belts
- Texture
- Schistose, often with staurolite porphyroblasts twinned in a cross shape
- Grain size
- Medium-grained (grains 0.25 to 2 mm)
- Composition
- Mica-rich schist with staurolite, often with almandine garnet, kyanite, biotite or sillimanite
Where rockhounds find staurolite schist
Classic worldwide localities
- Taos County, New Mexico, USA
- Fannin County, Georgia, USA
- Brittany, France
- Ticino, Switzerland
- Minas Gerais, Brazil
Field-hunting tip
Where it forms: metamorphic belts. If you start seeing staurolite, muscovite, biotite in float, you are in the right ground.
Common questions
How do you identify staurolite schist?+
Where is staurolite schist found?+
What minerals are found with staurolite schist?+
What kind of rock does staurolite schist form in?+
What is staurolite schist used for?+
Find staurolite schist on the map
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