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.
Is this tetradymite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry 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.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tetradymite leaves a lead-gray streak.
- 3Read the lusterHold the specimen under a strong light. Tetradymite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: steel-gray, silver-white.
- 5Look at form & habitCrystal 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.
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
- 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 spotsClassic 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 — that is 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.
Common questions
How do you identify tetradymite?+
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Can I find tetradymite in the United States?+
How much is tetradymite worth?+
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Find tetradymite on the map
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