Carlosturanite is a rare, fibrous magnesium silicate mineral typically found as asbestiform aggregates within serpentinized ultramafic rocks. It is most notable for its striking silky luster and its discovery in the alpine metamorphic terranes of northern Italy. Collectors should handle specimens carefully due to their fibrous, asbestos-like nature.
Is this carlosturanite?
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 carlosturanite with a known reference. Carlosturanite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: whitish.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous, pearly.
- 4Match the color rangeCompare against the expected color range: light brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous.
Often confused with
Carlosturanite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Carlosturanite leaves whitish, Chrysotile leaves white; luster reads vitreous, pearly on Carlosturanite and silky on Chrysotile.
How to tell apart: Streak differs, so Carlosturanite leaves whitish, Antigorite leaves white; luster reads vitreous, pearly on Carlosturanite and resinous, greasy, silky, waxy, earthy on Antigorite.
How to tell apart: Tremolite is the harder of the two (Mohs 5-6 vs. 2.5); streak differs, so Carlosturanite leaves whitish, Tremolite leaves white.
Often found alongside carlosturanite
Minerals reported to co-occur with carlosturanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mg,Fe,Ti)₂₁(Si,Al)₁₂O₂₈(OH)₃₄·H₂O
- Mohs hardness
- 2.5
- Density
- 2.63 g/cm³
- Colors
- Streak
- Whitish
- Luster
- Vitreous, pearly
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous
- Cleavage
- On {001}, very good; parting on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a network of veins crosscutting a metamorphic antigorite serpentinite, in an ophiolite
Where rockhounds find carlosturanite
Classic worldwide localities
- Taberg, Sweden
Field-hunting tip
Where it forms: In a network of veins crosscutting a metamorphic antigorite serpentinite, in an ophiolite. If you start seeing diopside, chrysotile, brucite in float, you are in the right ground. Typical habit: fibrous. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify carlosturanite?+
Where is carlosturanite found?+
Is carlosturanite safe to handle?+
What rocks look like carlosturanite?+
What minerals are found with carlosturanite?+
What kind of rock does carlosturanite form in?+
What is carlosturanite used for?+
Find carlosturanite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
