Lukrahnite is a rare calcium-copper arsenate mineral first identified in the world-famous Tsumeb mine. It typically occurs as small, delicate bladed crystals or radial sprays within oxidized zones of arsenic-rich base metal deposits.
Is this lukrahnite?
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 lukrahnite with a known reference. Lukrahnite 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. Lukrahnite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Lukrahnite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-green, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed crystals, radial aggregates, crusts.
Often confused with
Lukrahnite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Lukrahnite leaves yellow, Tsumcorite leaves yellowish.
How to tell apart: Streak differs, so Lukrahnite leaves yellow, Arseniosiderite leaves yellowish-brown; luster reads vitreous on Lukrahnite and silky on Arseniosiderite.
Often found alongside lukrahnite
Minerals reported to co-occur with lukrahnite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaCu(AsO₄)(AsO₃OH)
- Mohs hardness
- 3-4
- Density
- 4.67 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Bladed Crystals, Radial Aggregates, Crusts
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Mineral Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find lukrahnite
Classic worldwide localities
- Tsumeb Mine, Namibia
- Guanaco, Chile
Field-hunting tip
Look in hydrothermal mineral deposits country, the host setting where lukrahnite typically forms. If you start seeing tsumcorite, wulfenite, dolomite in float, you are in the right ground. Field specimens usually show a bladed crystals, radial aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find lukrahnite on the map
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