Monohydrocalcite is an uncommon hydrated calcium carbonate mineral that typically forms in evaporitic environments, alkaline lakes, or occasionally as a cave deposit. It is metastable and often converts to calcite over time if dehydrated, so collectors should store specimens in sealed containers to preserve their integrity.
Is this monohydrocalcite?
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 monohydrocalcite with a known reference. Monohydrocalcite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Monohydrocalcite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Monohydrocalcite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, gray, yellowish.
- 5Look at form & habitCrystal system: trigonal. Typical habit: hexagonal prisms, spherulitic aggregates, crusts.
Often confused with
Monohydrocalcite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside monohydrocalcite
Minerals reported to co-occur with monohydrocalcite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaCO₃·H₂O
- Mohs hardness
- 3
- Density
- 2.44 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Hexagonal Prisms, Spherulitic Aggregates, Crusts
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Saline Lake Sediments and Cave Environments
- Typical price
- $20-100 per specimen
Where rockhounds find monohydrocalcite
Classic worldwide localities
- Lake Issyk-Kul, Kyrgyzstan
- Green River Formation, USA
- Cave deposits, Australia
Field-hunting tip
Look in saline lake sediments and cave environments country, the host setting where monohydrocalcite typically forms. If you start seeing calcite, aragonite, halite in float, you are in the right ground. Field specimens usually show a hexagonal prisms, spherulitic aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify monohydrocalcite?+
Where is monohydrocalcite found?+
How much is monohydrocalcite worth?+
What rocks look like monohydrocalcite?+
What minerals are found with monohydrocalcite?+
What kind of rock does monohydrocalcite form in?+
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Find monohydrocalcite on the map
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