Neltnerite is a rare manganese silicate mineral that belongs to the braunite group, appearing as small, dark, submetallic crystals. It is primarily identified by its occurrence in specific manganese-rich metamorphic environments, most notably in the Tachgagalt mine in Morocco. Collectors should look for its distinct tetragonal crystal habit when evaluating potential specimens.
Is this neltnerite?
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 neltnerite with a known reference. Neltnerite sits at Mohs 6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: submetallic.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: equant to dipyramidal crystals.
Often confused with
Neltnerite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside neltnerite
Minerals reported to co-occur with neltnerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaMn⁶⁺₆SiO₁₂
- Mohs hardness
- 6
- Density
- 4.63 g/cm³
- Colors
- Streak
- Black
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Equant to dipyramidal crystals
- Cleavage
- Indistinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a vein with minerals containing manganese and calcium (Tachgagalt, Morocco)
Where rockhounds find neltnerite
Classic worldwide localities
- Manganese Creek Falls, Keeweenaw Co., Michigan, USA
- Tachgagalt, Anti-Atlas Mountains, Morocco
Field-hunting tip
Where it forms: In a vein with minerals containing manganese and calcium (Tachgagalt, Morocco). If you start seeing braunite, marokite, crednerite in float, you are in the right ground. Typical habit: equant to dipyramidal crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify neltnerite?+
Where is neltnerite found?+
What rocks look like neltnerite?+
What minerals are found with neltnerite?+
What kind of rock does neltnerite form in?+
What is neltnerite used for?+
Find neltnerite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
