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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: 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.
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[B₆O₈(OH)₄]₂·4H₂O
- Mohs hardness
- 3.5
- Density
- 2.027 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Bladed crystals, aggregates
- Cleavage
- {001} and {100}, perfect; {110}, fair
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a playa evaporite sequence (Tincalayu deposit, Argentina); at a desert borax spring (Eagle Borax Spring, California, USA)
Where rockhounds find aristarainite
Classic worldwide localities
- South Meridian claim and at Eagle Borax Spring, Furnace Creek district, Death Valley, Inyo Co., California, USA
- Tincalayu borax deposit, Salar del Hombre Muerto, Salta Province, Argentina
Field-hunting tip
Where it forms: In a playa evaporite sequence (Tincalayu deposit, Argentina); at a desert borax spring (Eagle Borax Spring, California, USA). If you start seeing borax, kernite, rivadavite in float, you are in the right ground. Typical habit: bladed crystals, aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify aristarainite?+
Where is aristarainite found?+
What rocks look like aristarainite?+
What minerals are found with aristarainite?+
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What is aristarainite used for?+
Find aristarainite on the map
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