Molybdite typically occurs as a bright yellow, fibrous, or earthy secondary mineral resulting from the oxidation of molybdenite. It is most commonly found as soft, delicate crusts or tufts in the weathered zones of molybdenum-rich ore deposits.
Is this molybdite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch molybdite with a known reference. Molybdite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: colorless, greenish yellow, light greenish yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: fibrous, earthy, pulverulent, or as crusts.
Often confused with
Molybdite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads adamantine on Molybdite and resinous on Sulfur.
How to tell apart: Molybdite is noticeably harder (Mohs 3-4 vs. 1.5-2); streak differs, so Molybdite leaves white, Orpiment leaves pale lemon-yellow; luster reads adamantine on Molybdite and resinous, pearly on cleavage surface on Orpiment.
Often found alongside molybdite
Minerals reported to co-occur with molybdite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MoO₃
- Mohs hardness
- 3-4
- Density
- 4.72 g/cm³
- Colors
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Fibrous, earthy, pulverulent, or as crusts
- Cleavage
- {100}, perfect; {001}, distinct
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- In cavities and coating molybdenite in a weathered quartz vein near its contact with topaz-quartz greisen
Where rockhounds find molybdite
Classic worldwide localities
- Krupka, Krušné hory Mountains, Czech Republic
Field-hunting tip
Where it forms: In cavities and coating molybdenite in a weathered quartz vein near its contact with topaz-quartz greisen. If you start seeing molybdenite, betpakdalite, quartz in float, you are in the right ground. Typical habit: fibrous, earthy, pulverulent, or as crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify molybdite?+
Where is molybdite found?+
What rocks look like molybdite?+
What minerals are found with molybdite?+
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What is molybdite used for?+
Find molybdite on the map
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