Beshtauite is a rare ammonium sulfite hydrate found as a secondary mineral in volcanic fumaroles. It typically appears as small, colorless tabular crystals and is known primarily from its type locality at Mount Beshtau in the Caucasus Mountains.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareSulfur Oxysalt family

Beshtauite

Hardness: ~2
Luster: Vitreous
Streak: White
Transparency: Transparent

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Is this beshtauite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch beshtauite with a known reference. Beshtauite sits at Mohs ~2, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

Beshtauite vs. its common look-alikes, and how to tell them apart in the field.

Often found alongside beshtauite

Minerals reported to co-occur with beshtauite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: (NH₄)₂(UO₂)(SO₄)₂·2H₂O
Mohs hardness: ~2
Density: 3.046 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular crystals
Cleavage: None
Fluorescence: Fluoresces green under SW and LW UV
Rarity: Rare
Uses: Collector
Host rock: A secondary mineral in the oxidation zone of a hydrothermal vein-type uranium deposit in porphyritic granite

Where rockhounds find beshtauite

Classic worldwide localities

Beshtau uranium deposit, Mount Beshtau, Stavropol region, Northern Caucasus, Russia

Field-hunting tip

Where it forms: A secondary mineral in the oxidation zone of a hydrothermal vein-type uranium deposit in porphyritic granite. If you start seeing rozenite, gypsum, lermontovite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify beshtauite?+

Mohs hardness is ~2. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is beshtauite found?+

Notable localities include Beshtau uranium deposit, Mount Beshtau, Stavropol region, Northern Caucasus, Russia.

Is beshtauite safe to handle?+

Beshtauite contains uranium or thorium and calls for real care. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like beshtauite?+

Beshtauite is most often confused with Mascagnite, Letovicite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with beshtauite?+

Beshtauite commonly co-occurs with Rozenite, Gypsum, Lermontovite, Marcasite, Pyrite, Halloysite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does beshtauite form in?+

Where it forms: A secondary mineral in the oxidation zone of a hydrothermal vein-type uranium deposit in porphyritic granite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is beshtauite used for?+

Beshtauite is used in collector.

Find beshtauite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.