Uytenbogaardtite is a rare silver gold sulfide that typically occurs as microscopic inclusions within other sulfide minerals. It is almost exclusively found in epithermal precious metal deposits and requires microscopic examination for positive identification.
Is this uytenbogaardtite?
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 uytenbogaardtite with a known reference. Uytenbogaardtite sits at Mohs ~2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: gray white.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: microscopic crystals.
Often confused with
Uytenbogaardtite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside uytenbogaardtite
Minerals reported to co-occur with uytenbogaardtite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ag₃AuS₂
- Mohs hardness
- ~2
- Density
- 8.34-8.45 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Microscopic crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In low-temperature hydrothermal Au–Ag quartz veins, in part of supergene origin
Where rockhounds find uytenbogaardtite
Classic worldwide localities
- Comstock Lode, Virginia City, Storey Co. (type locality), at the Bullfrog and Original Bullfrog mines, Bullfrog district, Nye Co., and in the Life Preserver mine, Tolicha district, Nevada, USA
- Equity mine, near Creede, Mineral Co., Colorado, USA
- Morning Star deposit, San Bernardino Co., California, USA
- Comstock mine, Dos Cabezos Mountains, Cochise Co., Arizona, USA
- Tambang Sawah, Benkoelen district, Sumatra (type locality), and on Java, at the Pongkor Au–Ag deposit and in the Cirotan Au–Ag–Sn–W deposit, Indonesia
- Milluri prospect, Potosí, Bolivia
Field-hunting tip
Where it forms: In low-temperature hydrothermal Au–Ag quartz veins, in part of supergene origin. If you start seeing acanthite, au–ag alloy, chlorargyrite in float, you are in the right ground. Typical habit: microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify uytenbogaardtite?+
Where is uytenbogaardtite found?+
Is uytenbogaardtite safe to handle?+
What rocks look like uytenbogaardtite?+
What minerals are found with uytenbogaardtite?+
What kind of rock does uytenbogaardtite form in?+
What is uytenbogaardtite used for?+
Find uytenbogaardtite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
