Cotunnite is a rare lead chloride mineral typically forming as a sublimation product at volcanic fumaroles or as an oxidation product of galena. Collectors look for its characteristic adamantine luster and thin, colorless to yellowish orthorhombic crystals. Due to its solubility and lead content, it should be kept in a dry display environment and handled with proper care.
Is this cotunnite?
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 cotunnite with a known reference. Cotunnite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Cotunnite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Cotunnite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellowish, greenish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular or prismatic crystals, also found as crystalline crusts or incrustations.
Often confused with
Cotunnite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside cotunnite
Minerals reported to co-occur with cotunnite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbCl₂
- Mohs hardness
- 2.5
- Density
- 5.3 g/cm³
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular or Prismatic Crystals, Also Found as Crystalline Crusts or Incrustations
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Fumaroles and Oxidized Zones of Lead-bearing Ore Deposits
- Typical price
- $50-500 depending on specimen quality and size
Where rockhounds find cotunnite
Classic worldwide localities
- Mount Vesuvius, Italy
- Lavrion District, Greece
- Tolbachik Volcano, Russia
- Sierra Gorda, Chile
Field-hunting tip
Look in fumaroles and oxidized zones of lead-bearing ore deposits country — that is the host setting where cotunnite typically forms. If you start seeing galena, anglesite, cerussite in float, you are in the right ground. Field specimens usually show a acicular or prismatic crystals, also found as crystalline crusts or incrustations habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify cotunnite?+
Where is cotunnite found?+
How much is cotunnite worth?+
Is cotunnite safe to handle?+
What rocks look like cotunnite?+
What minerals are found with cotunnite?+
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Find cotunnite on the map
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