Bismoclite is a rare bismuth oxychloride that typically forms in the oxidized zones of ore deposits. It is often identified by its pearly luster on cleavage surfaces and its significantly high density for a non-metallic appearing mineral.

Hardness

2.5

Mohs

Luster

Pearly

Streak

White

Transparency

Translucent

mineralrare

Bismoclite

Hardness: 2.5
Luster: Pearly
Streak: White
Transparency: Translucent

Is this bismoclite?

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 bismoclite with a known reference. Bismoclite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Bismoclite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Bismoclite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: white, gray, yellowish.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: platy crystals, crusts, massive.

Often confused with

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

How to tell apart: Luster reads pearly on Bismoclite and adamantine on Matlockite.

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Often found alongside bismoclite

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

All properties

Chemical formula: BiOCl
Mohs hardness: 2.5
Density: 7.96 g/cm³
Colors: White Gray Yellowish
Streak: White
Luster: Pearly
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Platy Crystals, Crusts, Massive
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Bismuth-bearing Ore Deposits
Typical price: $20-150 for thumbnail to small cabinet specimens

Where rockhounds find bismoclite

Classic worldwide localities

Bisbee, Arizona, USA
Bolivia
Saxony, Germany
Cornwall, UK

Field-hunting tip

Look in oxidized zones of bismuth-bearing ore deposits country — that is the host setting where bismoclite typically forms. If you start seeing bismuth, bismutite, bismite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify bismoclite?+

Mohs hardness is 2.5. It typically shows a pearly luster. The streak is white. Common colors include white, gray, yellowish.

Where is bismoclite found?+

Notable localities include Bisbee, Arizona, USA; Bolivia; Saxony, Germany; Cornwall, UK.

How much is bismoclite worth?+

Typical asking prices fall in the range of $20-150 for thumbnail to small cabinet specimens. Quality, size, and provenance can move individual specimens well outside that range.

Is bismoclite safe to handle?+

It contains toxic constituents. Contains bismuth and chlorine; wash hands thoroughly after handling and avoid inhaling dust or powder. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like bismoclite?+

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

What minerals are found with bismoclite?+

Bismoclite commonly co-occurs with Bismuth, Bismutite, Bismite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does bismoclite form in?+

Bismoclite typically forms in oxidized zones of bismuth-bearing ore deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is bismoclite used for?+

Bismoclite is used in collector.

Find bismoclite on the map

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