Tsumcorite is a rare zinc-lead arsenate mineral typically found as small, bright yellow to reddish-brown tabular crystals. It is most famous as a type-locality mineral from the Tsumeb Mine in Namibia, where it forms in oxidized polymetallic ore bodies. Collectors should look for its distinctive flattened crystal habit often associated with secondary minerals in the oxidized zones of lead-zinc deposits.
Is this tsumcorite?
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 tsumcorite with a known reference. Tsumcorite sits at Mohs 4.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tsumcorite leaves a yellowish streak.
- 3Read the lusterHold the specimen under a strong light. Tsumcorite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brown, orange, reddish-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, drusy coatings, spherical aggregates.
Often confused with
Tsumcorite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Tsumcorite is noticeably harder (Mohs 4.5 vs. 3.5); streak differs — Tsumcorite leaves yellowish, Adamite leaves white.
How to tell apart: Streak differs — Tsumcorite leaves yellowish, Legrandite leaves white.
How to tell apart: Streak differs — Tsumcorite leaves yellowish, Mimetite leaves white; luster reads vitreous on Tsumcorite and adamantine on Mimetite.
Often found alongside tsumcorite
Minerals reported to co-occur with tsumcorite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbZn₂(AsO₄)₂·H₂O
- Mohs hardness
- 4.5
- Density
- 5.34 g/cm³
- Streak
- Yellowish
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Drusy Coatings, Spherical Aggregates
- Cleavage
- Distinct On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Hydrothermal Base-metal Deposits
- Typical price
- $50-500 thumbnail depending on crystal definition
Where rockhounds find tsumcorite
Classic worldwide localities
- Tsumeb Mine, Namibia
- Mapimi, Mexico
- Laurion, Greece
- Broken Hill, Australia
Field-hunting tip
Look in oxidized zones of hydrothermal base-metal deposits country — that is the host setting where tsumcorite typically forms. If you start seeing smithsonite, cerussite, mimetite in float, you are in the right ground. Field specimens usually show a tabular crystals, drusy coatings, spherical aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find tsumcorite on the map
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