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, 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.
