Lehmannite is a rare sodium copper titanium arsenate. It is a sublimate around an active volcanic fumarole. It was first described from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia.
Is this lehmannite?
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 lehmannite with a known reference. Lehmannite sits at Mohs 7.5-8, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Lehmannite leaves a grayish green with olive hue streak.
- 3Read the lusterHold the specimen under a strong light. Lehmannite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark grayish green, olive-greenish black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals.
Often confused with
Lehmannite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Lehmannite leaves grayish green with olive hue, Yellow Beryl leaves white.
How to tell apart: Streak differs, so Lehmannite leaves grayish green with olive hue, Citrine leaves white.
How to tell apart: Streak differs, so Lehmannite leaves grayish green with olive hue, Topaz leaves white.
Often found alongside lehmannite
Minerals reported to co-occur with lehmannite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₁₈Cu₁₂TiO₈(AsO₄)₈FCl₅
- Mohs hardness
- 7.5-8
- Density
- 3.676 g/cm³
- Streak
- Grayish Green with Olive Hue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Gemstone
- Host rock
- Granite Pegmatites
Where rockhounds find lehmannite
Classic worldwide localities
- Arsenatnaya fumarole, Kamchatka, Russia
Field-hunting tip
Look in granite pegmatites country, the host setting where lehmannite typically forms. If you start seeing quartz, feldspar, mica in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify lehmannite?+
Where is lehmannite found?+
Is lehmannite safe to handle?+
What rocks look like lehmannite?+
What minerals are found with lehmannite?+
What kind of rock does lehmannite form in?+
What is lehmannite used for?+
Find lehmannite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
