Radium is an extremely rare, highly radioactive metallic element found only in trace amounts within uranium ores. It is never found in pure form in nature and requires extensive chemical extraction processes to isolate, making it essentially unavailable to the public.

Hardness

Mohs

Luster

Metallic

Streak

Metallic white

Transparency

Opaque

mineralrare

Radium

Hardness: ~2
Luster: Metallic
Streak: Metallic white
Transparency: Opaque

Is this radium?

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 radium with a known reference. Radium 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: metallic white.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: silvery-white, blackened-by-oxidation.
5
Look at form & habit
Crystal system: cubic. Typical habit: metallic crusts or disseminated grains.

Often found alongside radium

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

All properties

Chemical formula: Ra
Mohs hardness: ~2
Density: 5.5 g/cm³
Colors: Silvery-whiteBlackened-by-oxidation
Streak: Metallic white
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Metallic crusts or disseminated grains
Cleavage: None
Rarity: Rare
Uses: Historical medical research, Radiological calibration
Host rock: uranium-bearing mineral deposits

Where rockhounds find radium

1 mapped spots

Classic worldwide localities

Democratic Republic of the Congo
Canada
Czech Republic
United States

Field-hunting tip

Where it forms: uranium-bearing mineral deposits. If you start seeing uraninite, autunite, carnotite in float, you are in the right ground. Typical habit: metallic crusts or disseminated grains. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Nevada. Start trip planning there.

Browse 1 U.S. spots for radium →

Common questions

How do you identify radium?+

Mohs hardness is ~2. Luster: metallic. The streak is metallic white. Common colors include silvery-white, blackened-by-oxidation.

Where is radium found?+

Notable localities include Democratic Republic of the Congo; Canada; Czech Republic; United States.

Can I find radium in the United States?+

RockHoundR maps 1 radium rockhounding spots across 1 U.S. states. The top states are Nevada.

Is radium safe to handle?+

Radium contains uranium or thorium and calls for real care. Extremely hazardous; highly radioactive and poses severe health risks, including cancer and radiation sickness. It should never be handled without professional shielding and regulatory supervision.

What minerals are found with radium?+

Radium commonly co-occurs with uraninite, autunite, carnotite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does radium form in?+

Where it forms: uranium-bearing mineral deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is radium used for?+

Radium is used in historical medical research, radiological calibration.

Find radium on the map

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