Krennerite is a rare gold-silver telluride that forms in low-temperature hydrothermal veins. It is distinguished from its dimorph, calaverite, by its orthorhombic crystal structure and distinct striated habit.
Is this krennerite?
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 krennerite with a known reference. Krennerite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: greenish gray.
- 3Read the lusterHold the specimen under a strong light. Luster: very high metallic.
- 4Match the color rangeCompare against the expected color range: white, blackish yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: striated.
Often confused with
Krennerite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads very high metallic on Krennerite and metallic on Calaverite.
How to tell apart: Streak differs, so Krennerite leaves greenish gray, Sylvanite leaves steel-gray to silver-white; luster reads very high metallic on Krennerite and metallic, brilliant on Sylvanite.
How to tell apart: Streak differs, so Krennerite leaves greenish gray, Petzite leaves grayish black; luster reads very high metallic on Krennerite and metallic on Petzite.
Often found alongside krennerite
Minerals reported to co-occur with krennerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Au,Ag)Te₂
- Mohs hardness
- 2-3
- Density
- 8.62 g/cm³
- Colors
- WhiteBlackish yellow
- Streak
- Greenish gray
- Luster
- Very high metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Striated
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In hydrothermal veins with other tellurides
Where rockhounds find krennerite
1 mapped spotsClassic worldwide localities
- Smoky Hill mine, Boulder Co., Colorado, USA
- Central City district, Gilpin Co., Colorado, USA
- Campbell mine, Bisbee, and at Tombstone, Cochise Co., Arizona, USA
- Golden Sunlight mine, near Whitehall, Jefferson Co., Montana, USA
- Konstantin-Ovkoye gold deposit, Krasnoyarskii region, and the Bereznyakov gold deposit, Southern Ural Mountains, Russia
- Zhana-Tyube Au–Te deposit, northern Kazakhstan
Field-hunting tip
Where it forms: In hydrothermal veins with other tellurides. If you start seeing calaverite, coloradoite, sylvanite in float, you are in the right ground. Typical habit: striated. 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 krennerite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
