Thorikosite is a very rare lead oxychloride mineral primarily found in ancient lead-smelting slags at Laurium, Greece. It typically forms thin, yellowish, plate-like crystals associated with other rare lead-bearing species in slag cavities.

Hardness

Mohs

Luster

Adamantine

Streak

White

Transparency

Translucent

mineralrare

Thorikosite

Hardness: 3
Luster: Adamantine
Streak: White
Transparency: Translucent

Is this thorikosite?

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 thorikosite with a known reference. Thorikosite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Thorikosite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Thorikosite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: yellow, yellowish-white.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: platy crystals, crusts.

Often confused with

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

Often found alongside thorikosite

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

All properties

Chemical formula: Pb₃SbO₂(OH)₂Cl₃
Mohs hardness: 3
Density: 7.3 g/cm³
Colors: Yellow Yellowish-white
Streak: White
Luster: Adamantine
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Platy Crystals, Crusts
Cleavage: Perfect On {001}
Rarity: Rare
Uses: Collector
Host rock: Slag Dumps (ancient Mining Slag)
Typical price: $100-500 for high-quality micro-mounts

Where rockhounds find thorikosite

Classic worldwide localities

Laurium, Greece

Field-hunting tip

Look in slag dumps (ancient mining slag) country, the host setting where thorikosite typically forms. If you start seeing laurionite, fiedlerite, phosgenite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify thorikosite?+

Mohs hardness is 3. It typically shows a adamantine luster. The streak is white. Common colors include yellow, yellowish-white.

Where is thorikosite found?+

Notable localities include Laurium, Greece.

How much is thorikosite worth?+

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

Is thorikosite safe to handle?+

It contains toxic constituents. Contains lead, which is toxic if ingested or inhaled as dust. Wash hands thoroughly after handling specimens. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like thorikosite?+

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

What minerals are found with thorikosite?+

Thorikosite commonly co-occurs with Laurionite, Fiedlerite, Phosgenite, Anglesite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does thorikosite form in?+

Thorikosite typically forms in slag dumps (ancient mining slag). Working float back to the host body is the standard way to chase a fresh occurrence.

What is thorikosite used for?+

Thorikosite is used in collector.

Find thorikosite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.