Segerstromite is an exceptionally rare lead-arsenic mineral known primarily from the Tsumeb Mine in Namibia. It typically forms as small, colorless to white prismatic crystals in oxidized zones of ore deposits. Due to its extreme rarity and toxicity, it is sought after only by advanced systematic mineral collectors.
Is this segerstromite?
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 segerstromite with a known reference. Segerstromite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Segerstromite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Segerstromite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: prismatic crystals.
Often confused with
Segerstromite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside segerstromite
Minerals reported to co-occur with segerstromite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₃As₄O₁₂(OH)₂
- Mohs hardness
- 2
- Density
- 3.83 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Prismatic Crystals
- Cleavage
- Distinct On {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Polymetallic Deposits
- Typical price
- $200-1000+ per specimen depending on size and quality
Where rockhounds find segerstromite
Classic worldwide localities
- Tsumeb Mine, Namibia
Field-hunting tip
Look in hydrothermal polymetallic deposits country — that is the host setting where segerstromite typically forms. If you start seeing tsumebite, leadhillite, cerussite in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find segerstromite on the map
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