Teruggite is a rare calcium magnesium arsenate borate mineral typically found as small, delicate, yellow bladed crystals. It is primarily encountered in boron-rich evaporite deposits where it forms in association with other borate minerals. Due to its scarcity and arsenic content, it is primarily sought after by advanced mineral collectors.
Is this teruggite?
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 teruggite with a known reference. Teruggite 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. Teruggite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Teruggite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed crystals, radial aggregates.
Often confused with
Teruggite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside teruggite
Minerals reported to co-occur with teruggite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₄Mg(AsO₃OH)₂(B₄O₇)₂(OH)₂·4H₂O
- Mohs hardness
- 3
- Density
- 2.44 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Bladed Crystals, Radial Aggregates
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Borate-bearing Sedimentary Evaporite Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find teruggite
Classic worldwide localities
- Boron District, California, USA
- Kırka Boron Deposit, Turkey
Field-hunting tip
Look in borate-bearing sedimentary evaporite deposits country — that is the host setting where teruggite typically forms. If you start seeing colemanite, howlite, realgar in float, you are in the right ground. Field specimens usually show a bladed crystals, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify teruggite?+
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How much is teruggite worth?+
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What rocks look like teruggite?+
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Find teruggite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
