Spiridonovite is a rare copper silver telluride that forms black subhedral to anhedral grains. It is a secondary after precious metals and tellurides localized in quartz veins. Associated minerals include rickardite, vulcanite and cameronite. It was first described from Good Hope mine, Vulcan, Gunnison Co., Colorado, USA.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrarePlatinum Group Minerals family

Spiridonovite

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

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Is this spiridonovite?

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 spiridonovite with a known reference. Spiridonovite sits at Mohs 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. Spiridonovite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Spiridonovite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: black.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: subhedral to anhedral grains.

Often confused with

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

Often found alongside spiridonovite

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

All properties

Chemical formula: (Cu₁₋ₓAgₓ)₂Te, (x≈0.4)
Mohs hardness: 3.5
Density: 4.6 g/cm³
Colors: Black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Hexagonal
Crystal habit: Subhedral to Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector, Scientific Research
Host rock: Ultramafic Igneous Rocks

Where rockhounds find spiridonovite

Classic worldwide localities

Konder Massif, Russia
Norilsk, Russia

Field-hunting tip

Look in ultramafic igneous rocks country, the host setting where spiridonovite typically forms. If you start seeing platinum, sperrylite, chalcopyrite in float, you are in the right ground. Field specimens usually show a subhedral to anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify spiridonovite?+

Mohs hardness is 3.5. It typically shows a metallic luster. The streak is black. Common colors include black.

Where is spiridonovite found?+

Notable localities include Konder Massif, Russia; Norilsk, Russia.

Is spiridonovite safe to handle?+

It contains toxic constituents. Contains copper and tellurium, which are toxic if ingested or inhaled as dust. Wash hands thoroughly after handling and avoid creating dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like spiridonovite?+

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

What minerals are found with spiridonovite?+

Spiridonovite commonly co-occurs with Platinum, Sperrylite, Chalcopyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does spiridonovite form in?+

Spiridonovite typically forms in ultramafic igneous rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is spiridonovite used for?+

Spiridonovite is used in collector, scientific research.

Find spiridonovite on the map

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