Lammerite is a rare copper arsenate mineral that occurs as small, intense green, transparent crystals in oxidized hydrothermal ore deposits. It is highly sought after by advanced collectors for its distinct color and scarcity, often found as radiating groups on a matrix of weathered sulfide ores.
Is this lammerite?
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 lammerite with a known reference. Lammerite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Lammerite leaves a light green streak.
- 3Read the lusterHold the specimen under a strong light. Lammerite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: green, yellowish-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, radial aggregates.
Often confused with
Lammerite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Lammerite is noticeably harder (Mohs 3.5 vs. 2-2.5); streak differs — Lammerite leaves light green, Liroconite leaves pale blue.
How to tell apart: Streak differs — Lammerite leaves light green, Clinoclase leaves bluish-green.
How to tell apart: Streak differs — Lammerite leaves light green, Olivenite leaves olive-green; luster reads vitreous on Lammerite and adamantine on Olivenite.
Often found alongside lammerite
Minerals reported to co-occur with lammerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃(AsO₄)₂
- Mohs hardness
- 3.5
- Density
- 4.87 g/cm³
- Colors
- Streak
- Light Green
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Radial Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Copper-arsenic Veins
- Typical price
- $50-500 depending on specimen quality and rarity
Where rockhounds find lammerite
Classic worldwide localities
- Chuquicamata Mine, Chile
- Tsumeb Mine, Namibia
Field-hunting tip
Look in hydrothermal copper-arsenic veins country — that is the host setting where lammerite typically forms. If you start seeing enargite, pyrite, quartz in float, you are in the right ground. Field specimens usually show a prismatic crystals, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify lammerite?+
Where is lammerite found?+
How much is lammerite worth?+
Is lammerite safe to handle?+
What rocks look like lammerite?+
What minerals are found with lammerite?+
What kind of rock does lammerite form in?+
What is lammerite used for?+
Find lammerite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
