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 — Keyite leaves pale yellow, Duftite leaves light green; luster reads adamantine on Keyite and vitreous on Duftite.
How to tell apart: Streak differs — 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 — that is 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
How do you identify keyite?+
Where is keyite found?+
How much is keyite worth?+
Is keyite safe to handle?+
What rocks look like keyite?+
What minerals are found with keyite?+
What kind of rock does keyite form in?+
What is keyite used for?+
Find keyite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
