Tennantite-(Zn) is a member of the tetrahedrite-tennantite group characterized by a significant zinc content replacing copper in the crystal structure. It typically appears as sharp, metallic tetrahedral crystals found in hydrothermal sulfide deposits alongside other base metal minerals.

Hardness

3-4

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineraluncommonTetrahedrite Group family

Tennantite-(Zn)

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

Is this tennantite-(zn)?

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 tennantite-(zn) with a known reference. Tennantite-(Zn) 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. Streak: black.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: steel-gray, iron-black.
5
Look at form & habit
Crystal system: cubic. Typical habit: tetrahedral crystals, massive, granular.

Often confused with

Tennantite-(Zn) vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Streak differs, so Tennantite-(Zn) leaves black, Tennantite leaves reddish gray.

How to tell apart: Streak differs, so Tennantite-(Zn) leaves black, Enargite leaves grayish black.

Compare →

Often found alongside tennantite-(zn)

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

All properties

Chemical formula: Cu₆(Cu₄Zn₂)As₄S₁₃
Mohs hardness: 3-4
Density: 4.37-4.49 g/cm³
Colors: Steel-gray Iron-black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Tetrahedral crystals, massive, granular
Cleavage: None
Rarity: Uncommon
Uses: Collector, Ore of copper
Host rock: hydrothermal veins

Where rockhounds find tennantite-(zn)

Classic worldwide localities

Casapalca Mine, Peru
Tsumeb Mine, Namibia
Copper Queen Mine, USA
Lengenbach Quarry, Switzerland

Field-hunting tip

Where it forms: hydrothermal veins. If you start seeing chalcopyrite, galena, sphalerite in float, you are in the right ground. Typical habit: tetrahedral crystals, massive, granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tennantite-(zn)?+

Mohs hardness is 3-4. Luster: metallic. The streak is black. Common colors include steel-gray, iron-black.

Where is tennantite-(zn) found?+

Notable localities include Casapalca Mine, Peru; Tsumeb Mine, Namibia; Copper Queen Mine, USA; Lengenbach Quarry, Switzerland.

Is tennantite-(zn) safe to handle?+

Tennantite-(Zn) contains arsenic and copper and calls for real care. Contains arsenic and copper. Wash hands thoroughly after handling and avoid inhaling dust during preparation or cleaning.

What rocks look like tennantite-(zn)?+

Tennantite-(Zn) is most often confused with Tetrahedrite, Tennantite, Enargite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with tennantite-(zn)?+

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

What kind of rock does tennantite-(zn) form in?+

Where it forms: hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tennantite-(zn) used for?+

Tennantite-(Zn) is used in collector, ore of copper.

Find tennantite-(zn) on the map

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