Thorneite is an extremely rare lead sulfate-carbonate mineral typically found as a secondary mineral in old lead smelting slags. It usually forms small, transparent, tabular crystals that can be difficult to distinguish from other lead-bearing secondary minerals without chemical analysis.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Thorneite

Hardness: 2
Luster: Vitreous
Streak: White
Transparency: Transparent

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Is this thorneite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch thorneite with a known reference. Thorneite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Thorneite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Thorneite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, pale yellow.
5
Look at form & habit
Crystal system: trigonal. Typical habit: tabular crystals, clusters.

Often confused with

Thorneite vs. its common look-alikes — and how to tell them apart in the field.

mineral

Anglesite

Mohs 2.5-3

How to tell apart: Luster reads vitreous on Thorneite and adamantine on Anglesite.

How to tell apart: Cerussite is the harder of the two (Mohs 3-3.5 vs. 2); luster reads vitreous on Thorneite and adamantine on Cerussite.

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Often found alongside thorneite

Minerals reported to co-occur with thorneite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Pb₆(SO₄)₂(CO₃)O(OH)₂
Mohs hardness: 2
Density: 4.56 g/cm³
Colors: Yellow Pale Yellow
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Tabular Crystals, Clusters
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Altered Lead-rich Smelting Slags
Typical price: $100-500 for micro-mounts

Where rockhounds find thorneite

Classic worldwide localities

Thornbury, England
Ancient lead slags

Field-hunting tip

Look in altered lead-rich smelting slags country — that is the host setting where thorneite typically forms. If you start seeing galena, anglesite, cerussite in float, you are in the right ground. Field specimens usually show a tabular crystals, clusters habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify thorneite?+

Mohs hardness is 2. It typically shows a vitreous luster. The streak is white. Common colors include yellow, pale yellow.

Where is thorneite found?+

Notable localities include Thornbury, England; Ancient lead slags.

How much is thorneite worth?+

Typical asking prices fall in the range of $100-500 for micro-mounts. Quality, size, and provenance can move individual specimens well outside that range.

Is thorneite safe to handle?+

It contains toxic constituents. Contains lead. Avoid inhalation of dust or ingestion. Wash hands thoroughly after handling specimens. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like thorneite?+

Thorneite is most often confused with Anglesite, Cerussite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with thorneite?+

Thorneite commonly co-occurs with Galena, Anglesite, Cerussite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does thorneite form in?+

Thorneite typically forms in altered lead-rich smelting slags. Working float back to the host body is the standard way to chase a fresh occurrence.

What is thorneite used for?+

Thorneite is used in collector.

Find thorneite on the map

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