Vajdakite is a rare secondary mineral typically found as small, bright yellow tabular crystals in oxidation zones of uranium-molybdenum deposits. It is primarily known from the historic mining district of Jáchymov, where it forms in association with uranium minerals. Collectors value it for its vibrant color and rarity, often requiring magnification for proper identification.

Hardness

Mohs

Luster

Vitreous

Streak

Yellow

Transparency

Transparent

mineralrare

Vajdakite

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

Is this vajdakite?

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

Often confused with

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

mineral

Molybdite

Mohs 1-2

How to tell apart: Luster reads vitreous on Vajdakite and silky on Molybdite.

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Often found alongside vajdakite

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

All properties

Chemical formula: Mo⁶⁺O₂(OH)₂·H₂O
Mohs hardness: 2
Density: 4.15 g/cm³
Colors: Yellow Orange-yellow
Streak: Yellow
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $50-300 per specimen

Where rockhounds find vajdakite

Classic worldwide localities

Jachymov, Czech Republic

Field-hunting tip

Look in hydrothermal veins country — that is the host setting where vajdakite typically forms. If you start seeing uraninite, molybdenite, schrockingerite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify vajdakite?+

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

Where is vajdakite found?+

Notable localities include Jachymov, Czech Republic.

How much is vajdakite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like vajdakite?+

Vajdakite is most often confused with Molybdite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with vajdakite?+

Vajdakite commonly co-occurs with Uraninite, Molybdenite, Schrockingerite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does vajdakite form in?+

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

What is vajdakite used for?+

Vajdakite is used in collector.

Find vajdakite on the map

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