Mourite is an extremely rare molybdenum mineral typically found in hydrothermal veins associated with oxidized molybdenite deposits. It is best known for its striking deep blue to violet fibrous or needle-like crystal clusters, which make it highly sought after by systematic mineral collectors.
Is this mourite?
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 mourite with a known reference. Mourite 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. Mourite leaves a light blue streak.
- 3Read the lusterHold the specimen under a strong light. Mourite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: dark blue, deep violet.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous aggregates, needle-like crystals.
Often confused with
Mourite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Mourite leaves light blue, Molybdite leaves white.
How to tell apart: Mourite is noticeably harder (Mohs 3-4 vs. 1-2); streak differs, so Mourite leaves light blue, Ilsemannite leaves blue-black; luster reads adamantine on Mourite and dull on Ilsemannite.
Often found alongside mourite
Minerals reported to co-occur with mourite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (UO₂)(Mo⁶⁺)₅O₁₆·5H₂O
- Mohs hardness
- 3-4
- Density
- 3.78-4.12 g/cm³
- Colors
- Streak
- Light Blue
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous Aggregates, Needle-like Crystals
- Cleavage
- {100}, Pronounced
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
Where rockhounds find mourite
Classic worldwide localities
- Kyzyl-Chumysh, Kazakhstan
Field-hunting tip
Look in hydrothermal veins country, the host setting where mourite typically forms. If you start seeing molybdenite, quartz, pyrite in float, you are in the right ground. Field specimens usually show a fibrous aggregates, needle-like crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify mourite?+
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What rocks look like mourite?+
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Find mourite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
