Rivadavite is a rare borate mineral known primarily from the Tincalayu evaporite deposit in Argentina. It typically forms as small, clear to yellowish tabular crystals or granular masses within borate-rich salt environments.
Is this rivadavite?
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 rivadavite with a known reference. Rivadavite 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. Rivadavite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Rivadavite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, granular aggregates.
Often confused with
Rivadavite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Rivadavite is noticeably harder (Mohs 3.5 vs. 2-2.5); luster reads vitreous on Rivadavite and vitreous to earthy on Borax.
How to tell apart: Luster reads vitreous on Rivadavite and vitreous to pearly on Kernite.
How to tell apart: Rivadavite is noticeably harder (Mohs 3.5 vs. 2.5); luster reads vitreous on Rivadavite and silky on Ulexite.
Often found alongside rivadavite
Minerals reported to co-occur with rivadavite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₆MgB₂₄O₄₀·22H₂O
- Mohs hardness
- 3.5
- Density
- 2.44 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Granular Aggregates
- Cleavage
- None Observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Evaporite Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find rivadavite
Classic worldwide localities
- Tincalayu mine, Salta, Argentina
Field-hunting tip
Look in evaporite deposits country, the host setting where rivadavite typically forms. If you start seeing borax, kernite, ulexite in float, you are in the right ground. Field specimens usually show a tabular crystals, granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find rivadavite on the map
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