Cannonite is a rare bismuth sulfate mineral that typically occurs as small, transparent tabular crystals in oxidized mineral deposits. It is most famous from the Tintic district in Utah where it forms as a secondary mineral in mine dumps. Collectors prize it for its rarity and its distinct association with other secondary bismuth minerals.

Hardness

2-3

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Cannonite

Hardness: 2-3
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this cannonite?

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 cannonite with a known reference. Cannonite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Cannonite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Cannonite 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: orthorhombic. Typical habit: tabular crystals.

Often confused with

Cannonite 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 Cannonite and adamantine on Anglesite.

How to tell apart: Luster reads vitreous on Cannonite and pearly on Bismutite.

Compare →

Often found alongside cannonite

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

All properties

Chemical formula: Bi₂O(OH)₂SO₄
Mohs hardness: 2-3
Density: 5.5 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular Crystals
Cleavage: Perfect On {001}
Rarity: Rare
Uses: Collector
Host rock: Oxidized Hydrothermal Veins
Typical price: $50-300 per thumbnail specimen

Where rockhounds find cannonite

Classic worldwide localities

Tunnel Extension mine, Utah, USA
Tintic district, Utah, USA
Gold Hill, Utah, USA

Field-hunting tip

Look in oxidized hydrothermal veins country — that is the host setting where cannonite typically forms. If you start seeing bismutite, quartz, pyrite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify cannonite?+

Mohs hardness is 2-3. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is cannonite found?+

Notable localities include Tunnel Extension mine, Utah, USA; Tintic district, Utah, USA; Gold Hill, Utah, USA.

How much is cannonite worth?+

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

Is cannonite safe to handle?+

It contains toxic constituents. Contains bismuth, but primarily poses hazards due to associated toxic secondary minerals found in its environment; wash hands after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like cannonite?+

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

What minerals are found with cannonite?+

Cannonite commonly co-occurs with Bismutite, Quartz, Pyrite, Anglesite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does cannonite form in?+

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

What is cannonite used for?+

Cannonite is used in collector.

Find cannonite on the map

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