Magnesiostaurolite is a rare magnesium-dominant member of the staurolite group, often occurring in high-pressure metamorphic environments. It is best identified by its distinctive cruciform twinning habit and characteristic brown-to-reddish coloration in schists.
Is this magnesiostaurolite?
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 magnesiostaurolite with a known reference. Magnesiostaurolite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to resinous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: inclusions.
Often confused with
Magnesiostaurolite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside magnesiostaurolite
Minerals reported to co-occur with magnesiostaurolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg(Mg,Li)₃(Al,Mg)₁₈Si₈O₄₄(OH)₄
- Mohs hardness
- 7-7.5
- Density
- 3.54 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to resinous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Inclusions
- Rarity
- Rare
- Uses
- Collector
- Host rock
- From an ultra-high-pressure, coesite-bearing metamorphic terrane
Where rockhounds find magnesiostaurolite
Classic worldwide localities
- Dora-Maira massif, Italian Western Alps
Field-hunting tip
Where it forms: From an ultra-high-pressure, coesite-bearing metamorphic terrane. If you start seeing talc, clinochlore, rutile in float, you are in the right ground. Typical habit: inclusions. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify magnesiostaurolite?+
Where is magnesiostaurolite found?+
What rocks look like magnesiostaurolite?+
What minerals are found with magnesiostaurolite?+
What kind of rock does magnesiostaurolite form in?+
What is magnesiostaurolite used for?+
Find magnesiostaurolite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
