Jarandolite is a very rare calcium borate mineral known primarily from its type locality in Spain. It typically forms as delicate, white bladed crystals or radial clusters and is highly sought after by systematic mineral collectors.
Is this jarandolite?
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 jarandolite with a known reference. Jarandolite 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: white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular.
Often confused with
Jarandolite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside jarandolite
Minerals reported to co-occur with jarandolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaB₃O₄(OH)₃
- Mohs hardness
- 6
- Density
- 2.49 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Formed from abnormally highly saline water in a closed lacustrine basin of mixed volcanic tuffs and sedimentary clays and marls
Where rockhounds find jarandolite
Classic worldwide localities
- Jarandol basin, 280 km south of Belgrade, Serbia
Field-hunting tip
Where it forms: Formed from abnormally highly saline water in a closed lacustrine basin of mixed volcanic tuffs and sedimentary clays and marls. If you start seeing colemanite, howlite, lüneburgite in float, you are in the right ground. Typical habit: tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify jarandolite?+
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What rocks look like jarandolite?+
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Find jarandolite on the map
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