Chlorocalcite is a rare potassium calcium chloride mineral that typically forms as a fumarolic deposit or efflorescence. It is highly hygroscopic and requires careful storage in a dry environment to prevent it from deliquescing or dissolving due to atmospheric moisture.
Is this chlorocalcite?
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 chlorocalcite with a known reference. Chlorocalcite 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. Chlorocalcite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Chlorocalcite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: crusts, efflorescent coatings, granular aggregates.
Often confused with
Chlorocalcite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside chlorocalcite
Minerals reported to co-occur with chlorocalcite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KCaCl₃
- Mohs hardness
- 2.5
- Density
- 2.19 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Crusts, Efflorescent Coatings, Granular Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Fumarole Deposits
- Typical price
- $20-100 per specimen depending on size
Where rockhounds find chlorocalcite
Classic worldwide localities
- Mount Vesuvius, Italy
- Solikamsk, Russia
- Katzenbuckel, Germany
Field-hunting tip
Look in fumarole deposits country, the host setting where chlorocalcite typically forms. If you start seeing sylvite, halite, hematite in float, you are in the right ground. Field specimens usually show a crusts, efflorescent coatings, granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find chlorocalcite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
