Mattheddleite is a rare lead silicate-sulfate mineral named after the Scottish mineralogist Matthew Forster Heddle. It typically appears as small, colorless to pale yellow prismatic crystals found in the oxidized zones of lead-zinc mines, specifically in the Leadhills-Wanlockhead district of Scotland.
Is this mattheddleite?
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 mattheddleite with a known reference. Mattheddleite sits at Mohs 3.5-4.5, 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: colorless, white.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: aggregates, radial, rosette.
Often confused with
Mattheddleite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside mattheddleite
Minerals reported to co-occur with mattheddleite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₅(SiO₄)₁.₅(SO₄)₁.₅Cl
- Mohs hardness
- 3.5-4.5
- Density
- 6.96 g/cm³
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Aggregates, radial, rosette
- Cleavage
- On {0001}, or a parting
- Fluorescence
- Dull yellow under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Lining cavities in quartz which contain other oxidized lead minerals
Where rockhounds find mattheddleite
Classic worldwide localities
- Leadhills, Lanarkshire, Scotland
- Brae Fells, Red Gill, and Roughton Gill mines, Caldbeck Fells, Cumbria, England
- Dyfed, at the Esgair Hir mine, Bwlch-y-Esgair, Ceulanymaesmawr and the Darren mine, Penbont Rhydybeddau, Wales
Field-hunting tip
Where it forms: Lining cavities in quartz which contain other oxidized lead minerals. If you start seeing lanarkite, cerussite, anglesite in float, you are in the right ground. Typical habit: aggregates, radial, rosette. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify mattheddleite?+
Where is mattheddleite found?+
Is mattheddleite safe to handle?+
What rocks look like mattheddleite?+
What minerals are found with mattheddleite?+
What kind of rock does mattheddleite form in?+
What is mattheddleite used for?+
Find mattheddleite on the map
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