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 — that is 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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