Stannoidite is a rare copper-iron-tin sulfide mineral typically found in hydrothermal vein deposits. It is often identified by its distinct bronze color and metallic luster, usually occurring as massive grains rather than well-formed crystals.

Hardness

Mohs

Luster

Metallic

Streak

Dark brown-gray

Transparency

Opaque

mineraluncommon

Stannoidite

Hardness: ~4
Luster: Metallic
Streak: Dark brown-gray
Transparency: Opaque

Is this stannoidite?

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 stannoidite with a known reference. Stannoidite sits at Mohs ~4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: dark brown-gray.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: brass brown.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: massive.

Often confused with

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

mineral

Stannite

Mohs 4

How to tell apart: Streak differs, so Stannoidite leaves dark brown-gray, Stannite leaves blackish.

How to tell apart: Streak differs, so Stannoidite leaves dark brown-gray, Briartite leaves black.

Often found alongside stannoidite

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

All properties

Chemical formula: Cu₈Fe₂(Fe,Zn)Sn₂S₁₂
Mohs hardness: ~4
Density: 4.29 g/cm³
Colors: Brass brown
Streak: Dark brown-gray
Luster: Metallic
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Massive
Cleavage: None
Rarity: Uncommon
Uses: Collector
Host rock: In hydrothermal Sn–Cu sulfide deposits

Where rockhounds find stannoidite

Classic worldwide localities

Campbell mine, Bisbee, Cochise Co., Arizona, and at Butte, Silver Bow Co., Montana, USA
Konjo mine, Okayama Prefecture (type locality), Japan
Fukoku mine, Kyoto Prefecture, Japan
Hyogo Prefecture, at the Ikuno mine, Kanagase, Japan
Akenobe mine, Yabu, Japan
Tingha, New South Wales, Australia

Field-hunting tip

Where it forms: In hydrothermal Sn–Cu sulfide deposits. If you start seeing chalcopyrite, galena, tetrahedrite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify stannoidite?+

Mohs hardness is ~4. Luster: metallic. The streak is dark brown-gray. Common colors include brass brown.

Where is stannoidite found?+

Notable localities include Campbell mine, Bisbee, Cochise Co., Arizona, and at Butte, Silver Bow Co., Montana, USA; Konjo mine, Okayama Prefecture (type locality), Japan; Fukoku mine, Kyoto Prefecture, Japan; Hyogo Prefecture, at the Ikuno mine, Kanagase, Japan; Akenobe mine, Yabu, Japan.

Is stannoidite safe to handle?+

Stannoidite contains copper. Contains copper, iron, tin, and sulfur; handle with care and wash hands after handling to avoid ingestion or skin irritation.

What rocks look like stannoidite?+

Stannoidite is most often confused with Stannite, Briartite, Germanite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with stannoidite?+

Stannoidite commonly co-occurs with Chalcopyrite, Galena, Tetrahedrite, Stannite, Cassiterite, Siderite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does stannoidite form in?+

Where it forms: In hydrothermal Sn–Cu sulfide deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is stannoidite used for?+

Stannoidite is used in collector.

Find stannoidite on the map

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