Bearsite is a rare beryllium arsenate mineral typically found as small, colorless to white tabular crystals or radiating aggregates. It is most famously associated with the phosphate-rich pegmatites of Hagendorf, Germany, where it occurs as a secondary mineral in late-stage hydrothermal vugs.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrare

Bearsite

Hardness: 3
Luster: Vitreous
Streak: White
Transparency: Transparent to translucent

Is this bearsite?

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 bearsite with a known reference. Bearsite sits at Mohs 3, 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: white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: encrustations, fibrous, striated.

Often confused with

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

How to tell apart: Streak differs, so Bearsite leaves white, Paraschoepite leaves yellow.

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Often found alongside bearsite

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

All properties

Chemical formula: Be₂(AsO₄)(OH)·4H₂O
Mohs hardness: 3
Density: 1.8-2 g/cm³
Colors: White
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Monoclinic
Crystal habit: Encrustations, fibrous, striated
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: As a secondary mineral formed during the oxidation of an arsenic-bearing metal sulfide deposit associated with a felsite porphyry containing beryl

Where rockhounds find bearsite

Classic worldwide localities

Found in the Bota-Burum uranium deposit, 15 km south of Alakol’ Lake, Chu-Ili Mountains, Kazakhstan

Field-hunting tip

Where it forms: As a secondary mineral formed during the oxidation of an arsenic-bearing metal sulfide deposit associated with a felsite porphyry containing beryl. If you start seeing pharmacosiderite, arseniosiderite, scorodite–mansfieldite in float, you are in the right ground. Typical habit: encrustations, fibrous, striated. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify bearsite?+

Mohs hardness is 3. Luster: vitreous. The streak is white. Common colors include white.

Where is bearsite found?+

Notable localities include Found in the Bota-Burum uranium deposit, 15 km south of Alakol’ Lake, Chu-Ili Mountains, Kazakhstan.

Is bearsite safe to handle?+

Bearsite contains arsenic and beryllium and calls for real care. Contains arsenic, which is toxic. Handle with caution, wash hands after handling, and avoid inhaling dust.

What rocks look like bearsite?+

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

What minerals are found with bearsite?+

Bearsite commonly co-occurs with Pharmacosiderite, Arseniosiderite, Scorodite–mansfieldite, Conichalcite, Tyrolite, Sodium uranospinite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does bearsite form in?+

Where it forms: As a secondary mineral formed during the oxidation of an arsenic-bearing metal sulfide deposit associated with a felsite porphyry containing beryl. Working float back to the host body is the standard way to chase a fresh occurrence.

What is bearsite used for?+

Bearsite is used in collector.

Find bearsite on the map

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