Kenngottite is a rare silver arsenic sulfosalt often found as an accessory in complex hydrothermal vein systems. It is virtually indistinguishable from members of the polybasite-pearceite series without sophisticated chemical analysis like X-ray diffraction or EDS. Collectors look for its dark metallic, opaque appearance typically associated with other silver-bearing minerals.

Hardness

2-3

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrarePolybasite Group family

Kenngottite

Hardness: 2-3
Luster: Metallic
Streak: Black
Transparency: Opaque

No image

Is this kenngottite?

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

Often confused with

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

Often found alongside kenngottite

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

All properties

Chemical formula: (Ag,Cu)₁₆As₂S₁₁
Mohs hardness: 2-3
Density: 6.4-6.5 g/cm³
Colors: Iron-black Dark Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Tabular Crystals, Massive, Granular
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $50-500 thumbnail depending on locality

Where rockhounds find kenngottite

Classic worldwide localities

Radusa, North Macedonia
Guanajuato, Mexico
Freiberg, Germany

Field-hunting tip

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

Common questions

How do you identify kenngottite?+

Mohs hardness is 2-3. It typically shows a metallic luster. The streak is black. Common colors include iron-black, dark gray.

Where is kenngottite found?+

Notable localities include Radusa, North Macedonia; Guanajuato, Mexico; Freiberg, Germany.

How much is kenngottite worth?+

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

Is kenngottite safe to handle?+

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

What rocks look like kenngottite?+

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

What minerals are found with kenngottite?+

Kenngottite commonly co-occurs with Arsenopyrite, Pyrite, Sphalerite, Calcite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kenngottite form in?+

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

What is kenngottite used for?+

Kenngottite is used in collector.

Find kenngottite on the map

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