Holtstamite is a rare calcium-manganese aluminum garnet species discovered in the Wessels Mine of the Kalahari Manganese Field. It typically occurs as small, anhedral grains within manganese ore, requiring laboratory analysis to distinguish it from more common garnets like grossular. It is a highly sought-after specimen for specialized garnet collectors due to its restricted type locality.
Is this holtstamite?
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 holtstamite with a known reference. Holtstamite sits at Mohs 7 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Holtstamite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Holtstamite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellowish-brown, brown.
- 5Look at form & habitCrystal system: cubic. Typical habit: anhedral grains.
Often confused with
Holtstamite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside holtstamite
Minerals reported to co-occur with holtstamite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₃(Al,Mn³⁺)₂(SiO₄)₃
- Mohs hardness
- 7
- Density
- 3.75 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Cubic
- Crystal habit
- Anhedral Grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Manganiferous Silicate Rock
- Typical price
- $50-500 depending on specimen size and provenance
Where rockhounds find holtstamite
Classic worldwide localities
- Wessels Mine, South Africa
Field-hunting tip
Look in manganiferous silicate rock country — that is the host setting where holtstamite typically forms. If you start seeing ettringite, hausmannite, bixbyite in float, you are in the right ground. Field specimens usually show a anhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify holtstamite?+
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How much is holtstamite worth?+
What rocks look like holtstamite?+
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Find holtstamite on the map
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