Phosgenite is a rare lead chloride carbonate typically found as a secondary mineral in oxidized lead deposits. It is highly prized by collectors for its brilliant adamantine luster and distinct tetragonal prismatic crystal habit, which often fluoresce a characteristic bright yellow under UV light.
Is this phosgenite?
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 phosgenite with a known reference. Phosgenite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: white, gray, brownish yellow, greenish white, pinkish white.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: massive, prismatic, tabular.
Often confused with
Phosgenite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside phosgenite
Minerals reported to co-occur with phosgenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₂Cl₂CO₃
- Mohs hardness
- 2-3
- Density
- 6.12-6.15 g/cm³
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent to translucent
- Crystal system
- Tetragonal
- Crystal habit
- Massive, prismatic, tabular
- Cleavage
- {001} and {110}, distinct; {100}, indistinct
- Fluorescence
- Weak yellow-orange under SW UV; yellow-orange under LW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Uncommon, typically formed by alteration of galena in the oxidized zone of hydrothermal lead deposits, or by reaction of sea water with other lead minerals
Where rockhounds find phosgenite
Classic worldwide localities
- Terrible mine, Isle, Custer Co., Colorado, USA
- Mammoth mine, Tiger, Pinal Co., Arizona, USA
- Stevenson-Bennett mine, Organ Mountains, Doña Ana Co., New Mexico, USA
- Bage and other mines, near Matlock, Derbyshire, and from a number of mines in Cornwall, England
- Italy, Monteponi and Montevecchio, near Iglesias, and from Gibbas, near Cagliari, Sardinia
- Slag from Laurium, Greece
Field-hunting tip
Where it forms: Uncommon, typically formed by alteration of galena in the oxidized zone of hydrothermal lead deposits, or by reaction of sea water with other lead minerals. If you start seeing cerussite, anglesite, matlockite in float, you are in the right ground. Typical habit: massive, prismatic, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify phosgenite?+
Where is phosgenite found?+
Is phosgenite safe to handle?+
What rocks look like phosgenite?+
What minerals are found with phosgenite?+
What kind of rock does phosgenite form in?+
What is phosgenite used for?+
Find phosgenite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
