Menezesite is a rare niobate mineral that occurs as small yellow octahedral crystals. It is found primarily within the carbonatite rocks of the Jacupiranga Mine in Brazil, often associated with secondary minerals like calcite and magnetite.
Is this menezesite?
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 menezesite with a known reference. Menezesite sits at Mohs ~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: vitreous.
- 4Match the color rangeCompare against the expected color range: reddish borwn.
- 5Look at form & habitCrystal system: cubic. Typical habit: rhombohedral crystals.
Often confused with
Menezesite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside menezesite
Minerals reported to co-occur with menezesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ba₃MgZr₄Nb₁₂O₄₂·12H₂O
- Mohs hardness
- ~4
- Density
- 4.181 g/cm³
- Colors
- Reddish borwn
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Cubic
- Crystal habit
- Rhombohedral crystals
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a vug in the contact zone between dolomite carbonatite and “jacupirangite” (a pyroxenite)
Where rockhounds find menezesite
Classic worldwide localities
- Jacupiranga mine, Cajati county, São Paulo state, Brazil
Field-hunting tip
Where it forms: In a vug in the contact zone between dolomite carbonatite and “jacupirangite” (a pyroxenite). If you start seeing dolomite, calcite, magnetite in float, you are in the right ground. Typical habit: rhombohedral crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify menezesite?+
Where is menezesite found?+
What rocks look like menezesite?+
What minerals are found with menezesite?+
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Find menezesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
