Sturmanite is a rare boron-bearing sulfate typically found as vibrant yellow-orange hexagonal prisms in manganese mines. It is highly prized by collectors for its sharp crystal form and intense fluorescence under ultraviolet light.
Is this sturmanite?
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 sturmanite with a known reference. Sturmanite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Sturmanite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Sturmanite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-orange, brown.
- 5Look at form & habitCrystal system: trigonal. Typical habit: hexagonal prismatic crystals, often with pyramidal terminations.
Often confused with
Sturmanite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside sturmanite
Minerals reported to co-occur with sturmanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₆(Fe³⁺,Al,Mn³⁺)₂(SO₄)₂(B(OH)₄)(OH)₁₂·25H₂O
- Mohs hardness
- 2.5
- Density
- 1.85 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Hexagonal Prismatic Crystals, Often with Pyramidal Terminations
- Cleavage
- Perfect On {1010}
- Fluorescence
- Bright Yellow Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Manganese Ore Deposits
- Typical price
- $50-500 thumbnail, $300-2000+ cabinet
Where rockhounds find sturmanite
Classic worldwide localities
- Kalahari Manganese Fields, South Africa
Field-hunting tip
Look in manganese ore deposits country — that is the host setting where sturmanite typically forms. If you start seeing hausmannite, bultfonteinite, hematite in float, you are in the right ground. Field specimens usually show a hexagonal prismatic crystals, often with pyramidal terminations habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find sturmanite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
