Henritermierite is a rare calcium-manganese silicate member of the garnet group that crystallizes in the tetragonal system. It is primarily found as distinct, brownish, dodecahedral crystals in manganese-rich environments, most notably at the Tachgagalt mine in Morocco.
Is this henritermierite?
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 henritermierite with a known reference. Henritermierite 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: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: clove brown, orange brown.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: dodecahedral crystals.
Often confused with
Henritermierite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside henritermierite
Minerals reported to co-occur with henritermierite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₃Mn³⁺₂(SiO₄)₂(OH)₄
- Mohs hardness
- 6
- Density
- 3.34 g/cm³
- Colors
- Clove brownOrange brown
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Dodecahedral crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As small grains filling interstices between crystals of other minerals in a manganese ore deposit (Tachgagalt mine, Morocco)
Where rockhounds find henritermierite
Classic worldwide localities
- Tachgagalt manganese mine, Anti-Atlas Mountains, Morocco
- N'Chwaning and Wessels mines, near Kuruman, Cape Province, South Africa
Field-hunting tip
Where it forms: As small grains filling interstices between crystals of other minerals in a manganese ore deposit (Tachgagalt mine, Morocco). If you start seeing marokite, hausmannite, gaudefroyite in float, you are in the right ground. Typical habit: dodecahedral crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify henritermierite?+
Where is henritermierite found?+
What rocks look like henritermierite?+
What minerals are found with henritermierite?+
What kind of rock does henritermierite form in?+
What is henritermierite used for?+
Find henritermierite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
