Molybdofornacite is a rare secondary mineral found in the oxidation zones of lead-bearing ore deposits. It typically appears as bright yellow to greenish-yellow tabular crystals or thin crusts, often associated with other rare arsenates and chromates at world-class localities like Tsumeb.

Hardness

Mohs

Luster

Adamantine

Streak

Yellow

Transparency

Translucent

mineralrareFornacite Group family

Molybdofornacite

Hardness: 3
Luster: Adamantine
Streak: Yellow
Transparency: Translucent

Is this molybdofornacite?

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 molybdofornacite with a known reference. Molybdofornacite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Molybdofornacite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Molybdofornacite typically shows a adamantine 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: tabular crystals, crusts, acicular aggregates.

Often confused with

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

How to tell apart: Streak differs — Molybdofornacite leaves yellow, Vauquelinite leaves greenish-yellow; luster reads adamantine on Molybdofornacite and resinous to adamantine on Vauquelinite.

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Often found alongside molybdofornacite

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

All properties

Chemical formula: Pb₂Cu(CrO₄)(AsO₄)(OH)
Mohs hardness: 3
Density: 6.08 g/cm³
Colors: Yellow Greenish-yellow
Streak: Yellow
Luster: Adamantine
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals, Crusts, Acicular Aggregates
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Oxidized Hydrothermal Zones in Polymetallic Deposits
Typical price: $50-500 depending on specimen quality

Where rockhounds find molybdofornacite

Classic worldwide localities

Tsumeb Mine, Namibia
Callenberg, Saxony, Germany

Field-hunting tip

Look in oxidized hydrothermal zones in polymetallic deposits country — that is the host setting where molybdofornacite typically forms. If you start seeing cerussite, duftite, mimetite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, acicular aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify molybdofornacite?+

Mohs hardness is 3. It typically shows a adamantine luster. The streak is yellow. Common colors include yellow, greenish-yellow.

Where is molybdofornacite found?+

Notable localities include Tsumeb Mine, Namibia; Callenberg, Saxony, Germany.

How much is molybdofornacite worth?+

Typical asking prices fall in the range of $50-500 depending on specimen quality. Quality, size, and provenance can move individual specimens well outside that range.

Is molybdofornacite safe to handle?+

It contains toxic constituents. Contains lead and arsenic; avoid inhalation of dust and wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like molybdofornacite?+

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

What minerals are found with molybdofornacite?+

Molybdofornacite commonly co-occurs with Cerussite, Duftite, Mimetite, Dioptase. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does molybdofornacite form in?+

Molybdofornacite typically forms in oxidized hydrothermal zones in polymetallic deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is molybdofornacite used for?+

Molybdofornacite is used in collector.

Find molybdofornacite on the map

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