Solongoite is a rare borate mineral found in boron-rich skarn deposits. It typically forms as small, clear to white tabular crystals or radiating sprays that are highly prized by systematic mineral collectors.
Is this solongoite?
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 solongoite with a known reference. Solongoite sits at Mohs 3.5, 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: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, radiating aggregates.
Often confused with
Solongoite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside solongoite
Minerals reported to co-occur with solongoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂B₃O₄(OH)₄Cl
- Mohs hardness
- 3.5
- Density
- 2.514 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular crystals, radiating aggregates
- Cleavage
- One, imperfect, parallel elongation
- Rarity
- Rare
- Uses
- Collector
- Host rock
- From a drillhole into a contact metamorphic boron deposit at a depth of 400 m
Where rockhounds find solongoite
Classic worldwide localities
- Solongo boron deposit, Buryatia, Russia
Field-hunting tip
Where it forms: From a drillhole into a contact metamorphic boron deposit at a depth of 400 m. If you start seeing szaibélyite, andradite–grossular, kurchatovite in float, you are in the right ground. Typical habit: tabular crystals, radiating aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify solongoite?+
Where is solongoite found?+
What rocks look like solongoite?+
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Find solongoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
