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, so 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, 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.