Sidpietersite is a very rare lead thiosulfate mineral found primarily in the oxidation zones of lead deposits. It is best identified by its vibrant yellow, thin tabular crystals that appear in the complex mineral assemblages of the Tsumeb Mine.
Is this sidpietersite?
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 sidpietersite with a known reference. Sidpietersite sits at Mohs 1-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white to cream-white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to pearly.
- 4Match the color rangeCompare against the expected color range: colorless, cream white, beige.
- 5Look at form & habitCrystal system: triclinic. Typical habit: earthy, nodular, radial.
Often confused with
Sidpietersite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to pearly on Sidpietersite and adamantine to resinous, pearly on cleavage surfaces on Lanarkite.
How to tell apart: Luster reads vitreous to pearly on Sidpietersite and resinous to adamantine, pearly on {001} on Leadhillite.
Often found alongside sidpietersite
Minerals reported to co-occur with sidpietersite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₄(S₂O₃)O₂(OH)₂
- Mohs hardness
- 1-2
- Density
- 6.765 g/cm³
- Streak
- White to cream-white
- Luster
- Vitreous to pearly
- Transparency
- Transparent to opaque
- Crystal system
- Triclinic
- Crystal habit
- Earthy, nodular, radial
- Cleavage
- Perpendicular to [011]
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A very rare late-stage alteration product of galena in the oxidized zone of a dolostone-hosted hydrothermal polymetallic ore deposit
Where rockhounds find sidpietersite
Classic worldwide localities
- Tsumeb, Namibia
Field-hunting tip
Where it forms: A very rare late-stage alteration product of galena in the oxidized zone of a dolostone-hosted hydrothermal polymetallic ore deposit. If you start seeing smithsonite, zincite, greenockite in float, you are in the right ground. Typical habit: earthy, nodular, radial. Train your eye for that shape before scanning the outcrop.
Common questions
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Find sidpietersite on the map
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