Meymacite is a rare hydrated tungsten oxide that typically forms as an earthy, yellow to brownish coating on other tungsten-bearing minerals. It is primarily found as a secondary alteration product in weathered hydrothermal tungsten deposits and is highly prized by mineral collectors specializing in rare species.
Is this meymacite?
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 meymacite with a known reference. Meymacite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brownish yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous to vitreous.
- 4Match the color rangeCompare against the expected color range: yellow brown.
- 5Look at form & habitCrystal system: amorphous. Typical habit: powdery.
Often confused with
Meymacite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside meymacite
Minerals reported to co-occur with meymacite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- WO₃·2H₂O
- Mohs hardness
- 2-3
- Density
- 3.94-4.10 g/cm³
- Colors
- Streak
- Brownish yellow
- Luster
- Resinous to vitreous
- Transparency
- Semitransparent
- Crystal system
- Amorphous
- Crystal habit
- Powdery
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An alteration product in tungsten deposits
Where rockhounds find meymacite
Classic worldwide localities
- Nzombe, Kivu Province, Congo (Zaire)
- Meymac, Corrèze, France
- Genna Gureu, near Orroli, Sardinia, Italy
- Clara Mine, near Oberwolfach, Black Forest, Germany
Field-hunting tip
Where it forms: An alteration product in tungsten deposits. If you start seeing scheelite, ferberite, quartz in float, you are in the right ground. Typical habit: powdery. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify meymacite?+
Where is meymacite found?+
What rocks look like meymacite?+
What minerals are found with meymacite?+
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Find meymacite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
