Keyite is a rare copper-zinc arsenate mineral best known for its occurrence in the Tsumeb Mine. It typically forms as small, tabular green-colored crystals that are highly sought after by advanced collectors of rare species.
Is this keyite?
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 keyite with a known reference. Keyite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Keyite leaves a pale yellow streak.
- 3Read the lusterHold the specimen under a strong light. Keyite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: green, yellow-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals.
Often confused with
Keyite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Keyite leaves pale yellow, Duftite leaves light green; luster reads adamantine on Keyite and vitreous on Duftite.
How to tell apart: Streak differs, so Keyite leaves pale yellow, Conichalcite leaves light green; luster reads adamantine on Keyite and vitreous on Conichalcite.
Often found alongside keyite
Minerals reported to co-occur with keyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃Zn₄(AsO₄)₂(AsO₃OH)₂·2H₂O
- Mohs hardness
- 3-4
- Density
- 5.6 g/cm³
- Colors
- Streak
- Pale Yellow
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Mineral Deposits
- Typical price
- $100-1000+ per specimen
Where rockhounds find keyite
Classic worldwide localities
- Tsumeb Mine, Namibia
Field-hunting tip
Look in hydrothermal mineral deposits country, the host setting where keyite typically forms. If you start seeing duftite, tennantite, chalcocite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find keyite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
