Čejkaite is an extremely rare secondary uranium carbonate mineral found primarily in the Jachymov mining district. It typically forms thin tabular crystals or delicate crusts and is identified by its association with other secondary uranium minerals in oxidized zones.

Hardness

Mohs

Luster

Vitreous

Streak

Light yellow

Transparency

Translucent

mineralrareCarbonate Mineral family

Čejkaite

Hardness: 2
Luster: Vitreous
Streak: Light yellow
Transparency: Translucent

Is this čejkaite?

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 čejkaite with a known reference. Čejkaite 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: light yellow.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: pale yellow, beige.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: microscopic crystals, pseudo hexagonal.

Often confused with

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

mineral

Andersonite

Mohs 2.5

How to tell apart: Streak differs, so Čejkaite leaves light yellow, Andersonite leaves white.

How to tell apart: Streak differs, so Čejkaite leaves light yellow, Liebigite leaves yellow white.

Compare →

Often found alongside čejkaite

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

All properties

Chemical formula: Na₄(UO₂)(CO₃)₃
Mohs hardness: 2
Density: 3.67 g/cm³
Colors: Pale yellow Beige
Streak: Light yellow
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Microscopic crystals, pseudo hexagonal
Fluorescence: Weak yellow under SW UV; weak greenish yellow under LW UV
Rarity: Rare
Uses: Collector
Host rock: Secondary mineral associated with decomposed uraninite

Where rockhounds find čejkaite

Classic worldwide localities

Jachymov, NW Bohemia, Czech Republic (type locality)

Field-hunting tip

Where it forms: Secondary mineral associated with decomposed uraninite. If you start seeing andersonite, schröckingerite in float, you are in the right ground. Typical habit: microscopic crystals, pseudo hexagonal. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify čejkaite?+

Mohs hardness is 2. Luster: vitreous. The streak is light yellow. Common colors include pale yellow, beige.

Where is čejkaite found?+

Notable localities include Jachymov, NW Bohemia, Czech Republic (type locality).

Is čejkaite safe to handle?+

Čejkaite contains uranium or thorium and calls for real care. Contains uranium; store away from other minerals, handle with gloves, and wash hands thoroughly after contact.

What rocks look like čejkaite?+

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

What minerals are found with čejkaite?+

Čejkaite commonly co-occurs with Andersonite, Schröckingerite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does čejkaite form in?+

Where it forms: Secondary mineral associated with decomposed uraninite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is čejkaite used for?+

Čejkaite is used in collector.

Find čejkaite on the map

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