Fischesserite is an extremely rare silver-gold selenide typically found in trace amounts in epithermal deposits. It is best identified by its association with other selenide minerals and metallic luster, usually requiring analytical verification due to its microscopic habit.

Hardness

2.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareEucairite Group family

Fischesserite

Hardness: 2.5
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this fischesserite?

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 fischesserite with a known reference. Fischesserite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Fischesserite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Fischesserite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: silver-white, pale yellow.
5
Look at form & habit
Crystal system: cubic. Typical habit: anhedral grains, massive, granular.

Often confused with

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

mineral

Petzite

Mohs 2.5-3

How to tell apart: Streak differs — Fischesserite leaves black, Petzite leaves iron-black.

How to tell apart: Streak differs — Fischesserite leaves black, Aguilarite leaves lead-gray.

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Often found alongside fischesserite

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

All properties

Chemical formula: Ag₃AuSe₂
Mohs hardness: 2.5
Density: 8.3 g/cm³
Colors: Silver-white Pale Yellow
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Anhedral Grains, Massive, Granular
Cleavage: None
Rarity: Rare
Uses: Collector, Research
Host rock: Epithermal Hydrothermal Veins
Typical price: $100-500 thumbnail

Where rockhounds find fischesserite

Classic worldwide localities

Tilkerode, Germany
Kurnakovsky, Russia
Goldfield, Nevada, USA

Field-hunting tip

Look in epithermal hydrothermal veins country — that is the host setting where fischesserite typically forms. If you start seeing clausthalite, berzelianite, umanskite in float, you are in the right ground. Field specimens usually show a anhedral grains, massive, granular habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify fischesserite?+

Mohs hardness is 2.5. It typically shows a metallic luster. The streak is black. Common colors include silver-white, pale yellow.

Where is fischesserite found?+

Notable localities include Tilkerode, Germany; Kurnakovsky, Russia; Goldfield, Nevada, USA.

How much is fischesserite worth?+

Typical asking prices fall in the range of $100-500 thumbnail. Quality, size, and provenance can move individual specimens well outside that range.

Is fischesserite safe to handle?+

It contains toxic constituents. Contains selenium, which can be toxic if ingested or inhaled as dust. Handle with care and wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like fischesserite?+

Fischesserite is most often confused with Petzite, Eucairite, Aguilarite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with fischesserite?+

Fischesserite commonly co-occurs with Clausthalite, Berzelianite, Umanskite, Gold. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does fischesserite form in?+

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

What is fischesserite used for?+

Fischesserite is used in collector, research.

Find fischesserite on the map

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