Leydetite is a rare hydrated iron uranyl sulfate mineral typically found as a secondary mineral in uranium-bearing deposits. It forms distinct, small yellow prismatic crystals that are highly sought after by collectors of rare radioactive species.

Hardness

Mohs

Luster

Vitreous

Streak

Yellow

Transparency

Transparent

mineralrare

Leydetite

Hardness: 2
Luster: Vitreous
Streak: Yellow
Transparency: Transparent

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Is this leydetite?

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 leydetite with a known reference. Leydetite 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. Leydetite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Leydetite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, greenish-yellow.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: prismatic crystals.

Often confused with

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

mineral

Johannite

Mohs 2

How to tell apart: Streak differs, so Leydetite leaves yellow, Johannite leaves pale green.

How to tell apart: Luster reads vitreous on Leydetite and pearly on Zippeite.

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Often found alongside leydetite

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

All properties

Chemical formula: Fe(UO₂)(SO₄)₂·11H₂O
Mohs hardness: 2
Density: 2.47 g/cm³
Colors: Yellow Greenish-yellow
Streak: Yellow
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Prismatic Crystals
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins in Uranium Mines
Typical price: $100-500 thumbnail

Where rockhounds find leydetite

Classic worldwide localities

Freedom No. 2 mine, Utah, USA

Field-hunting tip

Look in hydrothermal veins in uranium mines country, the host setting where leydetite typically forms. If you start seeing gypsum, jarosite, zippeite in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify leydetite?+

Mohs hardness is 2. It typically shows a vitreous luster. The streak is yellow. Common colors include yellow, greenish-yellow.

Where is leydetite found?+

Notable localities include Freedom No. 2 mine, Utah, USA.

How much is leydetite worth?+

Typical asking prices fall in the range of $100-500 thumbnail. Quality, size, and provenance can move individual specimens well outside that range.

Is leydetite safe to handle?+

This mineral is radioactive. Contains uranium; standard radioactive mineral handling precautions apply, such as washing hands after handling and storing away from living areas. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like leydetite?+

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

What minerals are found with leydetite?+

Leydetite commonly co-occurs with Gypsum, Jarosite, Zippeite, Szomolnokite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does leydetite form in?+

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

What is leydetite used for?+

Leydetite is used in collector.

Find leydetite on the map

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