Petzite is a rare silver-gold telluride that typically occurs as massive, granular aggregates in hydrothermal veins. It is most easily identified by its metallic luster and dark gray color, often found in association with other rare tellurides and native gold.
Is this petzite?
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 petzite with a known reference. Petzite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: grayish black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: steel gray, iron black.
- 5Look at form & habitCrystal system: cubic. Typical habit: granular, massive.
Often confused with
Petzite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside petzite
Minerals reported to co-occur with petzite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ag₃AuTe₂
- Mohs hardness
- 2.5-3
- Density
- 8.7-9.4 g/cm³
- Colors
- Streak
- Grayish black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Granular, massive
- Cleavage
- {001}
- Rarity
- Rare
- Uses
- Collector, Ore of gold and silver
- Host rock
- With other tellurides in vein-controlled gold deposits
Where rockhounds find petzite
1 mapped spotsClassic worldwide localities
- Gold Hill, Boulder Co., Lake City, Hinsdale Co., and Leadville, Lake Co., Colorado, USA
- Golden Rule and Norwegian mines, Tuttletown, and the Jamestown mine, Tuolumne Co., in the Stanislaus and Melones mines, Carson Hill district, Calaveras Co., California, USA
- Buster mine, Olinghouse district, Washoe Co., Nevada, USA
- Săcărı̂mb (Nagyág) (type locality), Botés, and Baia Sprie (Felsőbánya), Romania
- Kochbulak gold deposit, Chatkal-Kuramin Mountains, eastern Uzbekistan
- Byn’govsk Au–Te deposit, Central Ural Mountains, Russia
Field-hunting tip
Where it forms: With other tellurides in vein-controlled gold deposits. If you start seeing gold, hessite, sylvanite in float, you are in the right ground. Typical habit: granular, massive. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Wisconsin. Start trip planning there.
Common questions
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Find petzite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
