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, 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.