Hocartite is a rare silver-tin sulfide mineral typically found in complex hydrothermal tin deposits. It is opaque with a metallic luster and is almost exclusively identified through laboratory methods like X-ray diffraction due to its visual similarity to more common stannite-group minerals.

Hardness

3-3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Hocartite

Hardness: 3-3.5
Luster: Metallic
Streak: Black
Transparency: Opaque

No image

Is this hocartite?

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 hocartite with a known reference. Hocartite sits at Mohs 3-3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Hocartite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Hocartite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: steel-gray, iron-black.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: massive, granular aggregates.

Often confused with

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

Often found alongside hocartite

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

All properties

Chemical formula: Ag₂SnFeS₄
Mohs hardness: 3-3.5
Density: 5.65 g/cm³
Colors: Steel-gray Iron-black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Tetragonal
Crystal habit: Massive, Granular Aggregates
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Tin-silver Veins
Typical price: $50-300 per specimen depending on size and rarity

Where rockhounds find hocartite

Classic worldwide localities

Chocaya Mine, Potosí, Bolivia
Santa Lucia Mine, Bolivia
Tasna, Bolivia

Field-hunting tip

Look in hydrothermal tin-silver veins country — that is the host setting where hocartite typically forms. If you start seeing stannite, pyrite, galena in float, you are in the right ground. Field specimens usually show a massive, granular aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify hocartite?+

Mohs hardness is 3-3.5. It typically shows a metallic luster. The streak is black. Common colors include steel-gray, iron-black.

Where is hocartite found?+

Notable localities include Chocaya Mine, Potosí, Bolivia; Santa Lucia Mine, Bolivia; Tasna, Bolivia.

How much is hocartite worth?+

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

Is hocartite safe to handle?+

It contains toxic constituents. Contains silver, tin, iron, and sulfur; handle with care to avoid ingestion of dust. Wash hands thoroughly after handling specimens. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like hocartite?+

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

What minerals are found with hocartite?+

Hocartite commonly co-occurs with Stannite, Pyrite, Galena, Sphalerite, Cassiterite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does hocartite form in?+

Hocartite typically forms in hydrothermal tin-silver veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is hocartite used for?+

Hocartite is used in collector.

Find hocartite on the map

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