Ishiharaite is a rare member of the tetrahedrite group characterized by its high indium content, primarily known from the Toyoha mine in Japan. It typically appears as metallic, grey to black tetrahedral crystals associated with zinc and lead sulfides in hydrothermal deposits.

Hardness

3-4

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareTetrahedrite Group family

Ishiharaite

Hardness: 3-4
Luster: Metallic
Streak: Black
Transparency: Opaque

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Is this ishiharaite?

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

Often confused with

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

How to tell apart: Streak differs — Ishiharaite leaves black, Sphalerite leaves white to yellow-brown; luster reads metallic on Ishiharaite and resinous to submetallic on Sphalerite.

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Often found alongside ishiharaite

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

All properties

Chemical formula: (Cu,Zn,Fe,In,Ag)₁₂(As,Sb)₄S₁₃
Mohs hardness: 3-4
Density: 4.6-4.8 g/cm³
Colors: Gray Black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Tetrahedral Crystals, Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $50-300 per specimen

Where rockhounds find ishiharaite

Classic worldwide localities

Toyoha mine, Japan

Field-hunting tip

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

Common questions

How do you identify ishiharaite?+

Mohs hardness is 3-4. It typically shows a metallic luster. The streak is black. Common colors include gray, black.

Where is ishiharaite found?+

Notable localities include Toyoha mine, Japan.

How much is ishiharaite worth?+

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

Is ishiharaite safe to handle?+

It contains toxic constituents. Contains arsenic and copper; avoid inhalation of dust and wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like ishiharaite?+

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

What minerals are found with ishiharaite?+

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

What kind of rock does ishiharaite form in?+

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

What is ishiharaite used for?+

Ishiharaite is used in collector.

Find ishiharaite on the map

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