Sidpietersite is a very rare lead thiosulfate mineral found primarily in the oxidation zones of lead deposits. It is best identified by its vibrant yellow, thin tabular crystals that appear in the complex mineral assemblages of the Tsumeb Mine.

Hardness

Mohs

Luster

Adamantine

Streak

Pale Yellow

Transparency

Transparent

mineralrare

Sidpietersite

Hardness: 2
Luster: Adamantine
Streak: Pale Yellow
Transparency: Transparent

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Is this sidpietersite?

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 sidpietersite with a known reference. Sidpietersite 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. Sidpietersite leaves a pale yellow streak.
3
Read the luster
Hold the specimen under a strong light. Sidpietersite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: yellow, yellowish-orange.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, subparallel aggregates.

Often confused with

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

mineral

Lanarkite

Mohs 2-2.5

How to tell apart: Streak differs — Sidpietersite leaves pale yellow, Lanarkite leaves white.

How to tell apart: Streak differs — Sidpietersite leaves pale yellow, Leadhillite leaves white.

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Often found alongside sidpietersite

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

All properties

Chemical formula: Pb₄(S₂O₃)O₂(OH)₂
Mohs hardness: 2
Density: 4.56 g/cm³
Colors: Yellow Yellowish-orange
Streak: Pale Yellow
Luster: Adamantine
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular Crystals, Subparallel Aggregates
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Oxidized Hydrothermal Lead Deposits
Typical price: $200-2000+ per specimen

Where rockhounds find sidpietersite

Classic worldwide localities

Tsumeb Mine, Namibia

Field-hunting tip

Look in oxidized hydrothermal lead deposits country — that is the host setting where sidpietersite typically forms. If you start seeing galena, anglesite, cerussite in float, you are in the right ground. Field specimens usually show a tabular crystals, subparallel aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sidpietersite?+

Mohs hardness is 2. It typically shows a adamantine luster. The streak is pale yellow. Common colors include yellow, yellowish-orange.

Where is sidpietersite found?+

Notable localities include Tsumeb Mine, Namibia.

How much is sidpietersite worth?+

Typical asking prices fall in the range of $200-2000+ per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is sidpietersite safe to handle?+

It contains toxic constituents. Contains lead, which is toxic. Handle with care, wash hands after touching, and do not inhale dust or ingest. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like sidpietersite?+

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

What minerals are found with sidpietersite?+

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

What kind of rock does sidpietersite form in?+

Sidpietersite typically forms in oxidized hydrothermal lead deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sidpietersite used for?+

Sidpietersite is used in collector.

Find sidpietersite on the map

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