Inyoite is a rare hydrated calcium borate mineral that forms as prismatic crystals or radiating clusters within evaporite deposits. Collectors typically look for its sharp, glassy crystals in classic borate-rich environments where it is often associated with other borate species.
Is this inyoite?
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 inyoite with a known reference. Inyoite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Inyoite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Inyoite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, radial aggregates, crusts.
Often confused with
Inyoite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Priceite is the harder of the two (Mohs 3-3.5 vs. 2); luster reads vitreous on Inyoite and dull on Priceite.
How to tell apart: Luster reads vitreous on Inyoite and silky on Ulexite.
How to tell apart: Luster reads vitreous on Inyoite and vitreous to earthy on Borax.
Often found alongside inyoite
Minerals reported to co-occur with inyoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂B₆O₆(OH)₁₀·8H₂O
- Mohs hardness
- 2
- Density
- 1.87 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Radial Aggregates, Crusts
- Cleavage
- Perfect On {010}
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Evaporite Deposits in Arid Lake Beds
- Typical price
- $10-60 for small mineral specimens
Where rockhounds find inyoite
Classic worldwide localities
- Inyo County, California, USA
- Salinas, New Brunswick, Canada
- Iletski, Russia
Field-hunting tip
Look in evaporite deposits in arid lake beds country — that is the host setting where inyoite typically forms. If you start seeing colemanite, ulexite, gypsum in float, you are in the right ground. Field specimens usually show a prismatic crystals, radial aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find inyoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
