Tetradymite is a distinct telluride mineral recognized by its metallic luster and perfect basal cleavage, often forming foliated, platy masses that resemble molybdenite. It is most commonly found in hydrothermal gold-bearing veins and contact metamorphic skarns. Collectors should look for its characteristic steel-gray color and sectile nature.

Hardness

1.5-2

Mohs

Luster

Metallic

Streak

Lead-gray

Transparency

Opaque

mineraluncommon

Tetradymite

Hardness: 1.5-2
Luster: Metallic
Streak: Lead-gray
Transparency: Opaque

Is this tetradymite?

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 tetradymite with a known reference. Tetradymite sits at Mohs 1.5-2, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Tetradymite leaves a lead-gray streak.
3
Read the luster
Hold the specimen under a strong light. Tetradymite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: steel-gray, silver-white.
5
Look at form & habit
Crystal system: trigonal. Typical habit: tabular crystals, foliated masses, bladed.

Often confused with

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

mineral

Molybdenite

Mohs 1-1.5

How to tell apart: Streak differs, so Tetradymite leaves lead-gray, Molybdenite leaves greenish-gray.

Often found alongside tetradymite

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

All properties

Chemical formula: Bi₂Te₂S
Mohs hardness: 1.5-2
Density: 7.2-7.5 g/cm³
Colors: Steel-gray Silver-white
Streak: Lead-gray
Luster: Metallic
Transparency: Opaque
Crystal system: Trigonal
Crystal habit: Tabular Crystals, Foliated Masses, Bladed
Cleavage: Perfect Basal
Rarity: Uncommon
Uses: Collector, Ore of Tellurium
Host rock: Hydrothermal Veins, Contact Metamorphic Deposits
Typical price: $20-150 thumbnail

Where rockhounds find tetradymite

2 mapped spots

Classic worldwide localities

Cheleken Peninsula, Turkmenistan
Schmiedefeld, Germany
Montgomery County, North Carolina, USA
Berezovskoye, Russia
Red Cloud Mine, Arizona, USA

Field-hunting tip

Look in hydrothermal veins, contact metamorphic deposits country, the host setting where tetradymite typically forms. If you start seeing gold, pyrite, chalcopyrite in float, you are in the right ground. Field specimens usually show a tabular crystals, foliated masses, bladed habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in New Mexico, North Carolina. Start trip planning there.

Browse 2 U.S. spots for tetradymite →

Common questions

How do you identify tetradymite?+

Mohs hardness is 1.5-2. It typically shows a metallic luster. The streak is lead-gray. Common colors include steel-gray, silver-white.

Where is tetradymite found?+

Notable localities include Cheleken Peninsula, Turkmenistan; Schmiedefeld, Germany; Montgomery County, North Carolina, USA; Berezovskoye, Russia; Red Cloud Mine, Arizona, USA.

Can I find tetradymite in the United States?+

RockHoundR maps 2 tetradymite rockhounding spots across 2 U.S. states. The top states are New Mexico, North Carolina.

How much is tetradymite worth?+

Typical asking prices fall in the range of $20-150 thumbnail. Quality, size, and provenance can move individual specimens well outside that range.

Is tetradymite safe to handle?+

It contains toxic constituents. Contains tellurium and bismuth; wash hands thoroughly after handling and avoid inhaling dust if crushing samples. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like tetradymite?+

Tetradymite is most often confused with Molybdenite, Bismuthinite, Tellurobismuthite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with tetradymite?+

Tetradymite commonly co-occurs with Gold, Pyrite, Chalcopyrite, Quartz, Tellurobismuthite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tetradymite form in?+

Tetradymite typically forms in hydrothermal veins, contact metamorphic deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tetradymite used for?+

Tetradymite is used in collector, ore of tellurium.

Find tetradymite on the map

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