Rhabdoborite-(W) is an exceptionally rare borate mineral found primarily in the contact-metasomatic boron deposits of the Tayozhnoye region in Russia. It typically occurs as small tabular crystals embedded within skarn mineral assemblages alongside magnetite and ludwigite. Collectors prize it for its restricted type locality and complex borate structure.
Is this rhabdoborite-(w)?
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 rhabdoborite-(w) with a known reference. Rhabdoborite-(W) sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Rhabdoborite-(W) leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Rhabdoborite-(W) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellow.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular crystals, subparallel aggregates.
Often confused with
Rhabdoborite-(W) vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside rhabdoborite-(w)
Minerals reported to co-occur with rhabdoborite-(w). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₁₂Mg(PO₄)₂B₆O₁₀(OH,O)₈
- Mohs hardness
- 5-6
- Density
- 3.31 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Tabular Crystals, Subparallel Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Boron-rich Magnesium Skarns
- Typical price
- n/a
Where rockhounds find rhabdoborite-(w)
Classic worldwide localities
- Tayozhnoye iron deposit, Yakutia, Russia
Field-hunting tip
Look in boron-rich magnesium skarns country — that is the host setting where rhabdoborite-(w) typically forms. If you start seeing ludwigite, forsterite, magnetite in float, you are in the right ground. Field specimens usually show a tabular crystals, subparallel aggregates habit, so train your eye for that shape before scanning the outcrop.






