Yarzhemskiite is a very rare calcium borate mineral that typically forms as small, clear, tabular crystals within evaporite sequences. It is primarily known from the Inder borate deposit in Kazakhstan and is highly sought after by systematic mineral collectors. Due to its solubility and rarity, it should be kept in a controlled, low-humidity environment.
Is this yarzhemskiite?
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 yarzhemskiite with a known reference. Yarzhemskiite 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. Yarzhemskiite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Yarzhemskiite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, massive.
Often confused with
Yarzhemskiite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside yarzhemskiite
Minerals reported to co-occur with yarzhemskiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaB₂O₄·H₂O
- Mohs hardness
- 3
- Density
- 2.44 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Massive
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Sedimentary Borate Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find yarzhemskiite
Classic worldwide localities
- Inder Borate Deposit, Kazakhstan
Field-hunting tip
Look in sedimentary borate deposits country — that is the host setting where yarzhemskiite typically forms. If you start seeing inderite, halite, gypsum in float, you are in the right ground. Field specimens usually show a tabular crystals, massive habit, so train your eye for that shape before scanning the outcrop.





