Eckerite is a very rare silver-copper arsenic sulfide mineral found in hydrothermal vein systems. It typically occurs as massive aggregates associated with other silver sulfosalts and is primarily sought after by advanced mineral collectors specializing in rare species.

Hardness

2.5-3

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Eckerite

Hardness: 2.5-3
Luster: Metallic
Streak: Black
Transparency: Opaque

No image

Is this eckerite?

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

Often confused with

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

Often found alongside eckerite

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

All properties

Chemical formula: Ag₂CuAsS₃
Mohs hardness: 2.5-3
Density: 4.4-4.5 g/cm³
Colors: White Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $50-500 depending on specimen quality

Where rockhounds find eckerite

Classic worldwide localities

Jáchymov, Czech Republic

Field-hunting tip

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

Common questions

How do you identify eckerite?+

Mohs hardness is 2.5-3. It typically shows a metallic luster. The streak is black. Common colors include white, gray.

Where is eckerite found?+

Notable localities include Jáchymov, Czech Republic.

How much is eckerite worth?+

Typical asking prices fall in the range of $50-500 depending on specimen quality. Quality, size, and provenance can move individual specimens well outside that range.

Is eckerite safe to handle?+

It contains toxic constituents. Contains arsenic and silver; wash hands thoroughly after handling and avoid inhaling dust if crushed. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like eckerite?+

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

What minerals are found with eckerite?+

Eckerite commonly co-occurs with Proustite, Pyrargyrite, Silver, Arsenopyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does eckerite form in?+

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

What is eckerite used for?+

Eckerite is used in collector.

Find eckerite on the map

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