Aristarainite is a rare borate mineral that typically occurs as white, bladed crystals within evaporite basins. It is primarily found in the Tincalayu deposit in Argentina, often forming associated clusters with other borate species like kernite and borax.
Is this aristarainite?
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 aristarainite with a known reference. Aristarainite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Aristarainite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Aristarainite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed crystals, aggregates.
Often confused with
Aristarainite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads vitreous on Aristarainite and vitreous to pearly on Kernite.
How to tell apart: Aristarainite is noticeably harder (Mohs 3.5 vs. 2-2.5); luster reads vitreous on Aristarainite and vitreous to earthy on Borax.
Often found alongside aristarainite
Minerals reported to co-occur with aristarainite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Mg(B₆O₁₀)(OH)₄·4H₂O
- Mohs hardness
- 3.5
- Density
- 2.21 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Bladed Crystals, Aggregates
- Cleavage
- Perfect On {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Evaporite Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find aristarainite
Classic worldwide localities
- Tincalayu Mine, Argentina
- Sijes, Argentina
Field-hunting tip
Look in evaporite deposits country — that is the host setting where aristarainite typically forms. If you start seeing borax, kernite, ezcurrite in float, you are in the right ground. Field specimens usually show a bladed crystals, aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find aristarainite on the map
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