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, 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.
