Sarcolite is an exceptionally rare silicate mineral primarily found in ejected blocks at Mount Vesuvius in Italy. It typically forms small, glassy, pinkish to reddish prismatic crystals in contact-metamorphosed limestone.
Is this sarcolite?
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 sarcolite with a known reference. Sarcolite sits at Mohs 6, 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.
- 4Match the color rangeCompare against the expected color range: flesh pink, red, reddish white.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: crystalline, pseudo cubic.
Often confused with
Sarcolite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside sarcolite
Minerals reported to co-occur with sarcolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₄Ca₁₂Al₈Si₁₂O₄₆(SiO₄,PO₄)(OH,H₂O)₄(CO₃,Cl)
- Mohs hardness
- 6
- Density
- 2.91-2.96 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Crystalline, pseudo cubic
- Cleavage
- Distinct on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In contact metamorphosed limestone-bearing volcanic ejecta
Where rockhounds find sarcolite
Classic worldwide localities
- Monte Somma and Vesuvius, Campania, and Anguillara Sabazia, Lazio, Italy
Field-hunting tip
Where it forms: In contact metamorphosed limestone-bearing volcanic ejecta. If you start seeing augite, gehlenite, garnet in float, you are in the right ground. Typical habit: crystalline, pseudo cubic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify sarcolite?+
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Find sarcolite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
