Borates are a group of boron-bearing minerals typically found in arid evaporite basins. They often form in massive or fibrous aggregates and are noted for being water-soluble, requiring careful storage away from humidity.
Is this borate?
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 borate with a known reference. Borate sits at Mohs 2-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Borate leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Borate typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, gray, yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive.
Often confused with
Borate vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside borate
Minerals reported to co-occur with borate. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- B₂O₃·nH₂O
- Mohs hardness
- 2-4
- Density
- 1.7-3.0 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Massive
- Cleavage
- Perfect
- Fluorescence
- Often Fluorescent
- Rarity
- Common
- Uses
- Industrial, Collector
- Host rock
- Evaporite Deposits
- Typical price
- $5-30 thumbnail, $20-100 cabinet
Where rockhounds find borate
2 mapped spotsClassic worldwide localities
- Boron
- California
- Turkey
- Argentina
Field-hunting tip
Look in evaporite deposits country, the host setting where borate typically forms. If you start seeing halite, gypsum, colemanite in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Oklahoma. Start trip planning there.
Common questions
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Find borate on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
