Susannite is a rare lead sulfate-carbonate mineral that is structurally related to leadhillite but crystallizes in the trigonal system. It typically forms as small, clear, rhombohedral crystals in the oxidation zones of lead mines, often occurring alongside other secondary lead minerals. It is highly prized by collectors for its brilliant adamantine luster and rarity in fine crystal specimens.
Is this susannite?
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 susannite with a known reference. Susannite sits at Mohs 2.5-3, 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 to resinous.
- 4Match the color rangeCompare against the expected color range: colorless, greenish, yellowish, light greenish yellow.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals, sometimes tabular.
Often confused with
Susannite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside susannite
Minerals reported to co-occur with susannite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₄SO₄(CO₃)₂(OH)₂
- Mohs hardness
- 2.5-3
- Density
- 6.55 g/cm³
- Streak
- White
- Luster
- Adamantine to resinous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral crystals, sometimes tabular
- Cleavage
- Perfect on {0001}
- Fluorescence
- Strong lemon yellow under SW and LW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in the oxidized zone of hydrothermal lead-bearing deposits, formed at temperatures above 80°C
Where rockhounds find susannite
Classic worldwide localities
- Mammoth-St. Anthony mine, Tiger, Pinal Co., Arizona, and at the Ecton mine, Audubon, Montgomery Co., Pennsylvania, USA
- Susanna mine, Leadhills, Lanarkshire, Scotland
- Caldbeck Fells, Cumbria, England
- Dyfed, from the Esgair Hir mine, Bwlch-y-Esgair, Ceulanymaesmawr, Wales
- Bwlch Glas mine, Wales
- Llechweddhelyg mine, Tir-y-Mynach, Wales
Field-hunting tip
Where it forms: A rare secondary mineral in the oxidized zone of hydrothermal lead-bearing deposits, formed at temperatures above 80°C. If you start seeing leadhillite, macphersonite, lanarkite in float, you are in the right ground. Typical habit: rhombohedral crystals, sometimes tabular. Train your eye for that shape before scanning the outcrop.
Common questions
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Find susannite on the map
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