Braunerite is a rare potassium calcium uranium carbonate. It was approved as a distinct mineral species in 2016. It was first described from Svornost mine, Jáchymov ore district, Western Bohemia, Czech Republic.

Hardness

3.5-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareCalcite Group family

Braunerite

Hardness: 3.5-4
Luster: Vitreous
Streak: White
Transparency: Translucent

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Is this braunerite?

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 braunerite with a known reference. Braunerite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Braunerite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Braunerite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: brown, yellowish-brown.
5
Look at form & habit
Crystal system: monoclinic.

Often confused with

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

Often found alongside braunerite

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

All properties

Chemical formula: K₂Ca(UO₂)(CO₃)₃·6H₂O
Mohs hardness: 3.5-4
Density: 3.4-3.5 g/cm³
Colors: Brown Yellowish-brown
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Cleavage: Perfect Rhombohedral
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins

Where rockhounds find braunerite

Classic worldwide localities

Czech Republic
Germany
Italy

Field-hunting tip

Look in hydrothermal veins country, the host setting where braunerite typically forms. If you start seeing calcite, dolomite, siderite in float, you are in the right ground.

Common questions

How do you identify braunerite?+

Mohs hardness is 3.5-4. It typically shows a vitreous luster. The streak is white. Common colors include brown, yellowish-brown.

Where is braunerite found?+

Notable localities include Czech Republic; Germany; Italy.

Is braunerite safe to handle?+

This mineral is radioactive. Contains uranium and is radioactive; store it apart from other specimens. Wash hands thoroughly after handling and avoid creating dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like braunerite?+

Braunerite is most often confused with Magnesite, Siderite, Calcite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with braunerite?+

Braunerite commonly co-occurs with Calcite, Dolomite, Siderite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does braunerite form in?+

Braunerite typically forms in hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is braunerite used for?+

Braunerite is used in collector.

Find braunerite on the map

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