Barstowite is a rare lead chloride carbonate mineral that typically forms as sharp, prismatic crystals in oxidized lead deposits. It is most famously found in the slag dumps of the Barstow mine in England and at the ancient mines of Laurium, Greece, often associated with phosgenite.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Barstowite

Hardness: 3
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this barstowite?

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 barstowite with a known reference. Barstowite 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. Barstowite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Barstowite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: prismatic crystals.

Often confused with

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

mineral

Phosgenite

Mohs 2.5-3

How to tell apart: Luster reads vitreous on Barstowite and adamantine on Phosgenite.

How to tell apart: Luster reads vitreous on Barstowite and adamantine on Cerussite.

Compare →

Often found alongside barstowite

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

All properties

Chemical formula: Pb₄Cl₆(CO₃)·H₂O
Mohs hardness: 3
Density: 3.58 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Prismatic Crystals
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Lead-bearing Veins
Typical price: $50-300 per specimen

Where rockhounds find barstowite

Classic worldwide localities

Barstow mine, England
Laurium, Greece

Field-hunting tip

Look in hydrothermal lead-bearing veins country — that is the host setting where barstowite typically forms. If you start seeing phosgenite, cerussite, galena in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify barstowite?+

Mohs hardness is 3. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is barstowite found?+

Notable localities include Barstow mine, England; Laurium, Greece.

How much is barstowite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is barstowite safe to handle?+

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

What rocks look like barstowite?+

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

What minerals are found with barstowite?+

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

What kind of rock does barstowite form in?+

Barstowite typically forms in hydrothermal lead-bearing veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is barstowite used for?+

Barstowite is used in collector.

Find barstowite on the map

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