Sylvanite is a rare gold-silver telluride characterized by its unique graphic, bladed crystal habit that resembles ancient cuneiform or scribbling. It is almost exclusively found in low-temperature hydrothermal gold-telluride deposits and is considered a significant but uncommon ore of gold.
Is this sylvanite?
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 sylvanite with a known reference. Sylvanite 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. Sylvanite leaves a gray streak.
- 3Read the lusterHold the specimen under a strong light. Sylvanite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: silver-white, steel-gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed crystals, skeletal growths, massive.
Often confused with
Sylvanite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Sylvanite leaves gray, Calaverite leaves yellowish-green.
How to tell apart: Streak differs — Sylvanite leaves gray, Krennerite leaves yellowish-grey.
How to tell apart: Streak differs — Sylvanite leaves gray, Petzite leaves iron-black.
Often found alongside sylvanite
Minerals reported to co-occur with sylvanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Au,Ag)₂Te₄
- Mohs hardness
- 1.5-2
- Density
- 8.1-8.2 g/cm³
- Colors
- Streak
- Gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Bladed Crystals, Skeletal Growths, Massive
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector, Ore of Gold
- Host rock
- Epithermal Hydrothermal Veins
- Typical price
- $20-150 thumbnail, $200-800 cabinet
Where rockhounds find sylvanite
3 mapped spotsClassic worldwide localities
- Crippled Creek, Colorado, USA
- Baia de Aries, Romania
- Kalgoorlie, Western Australia
- Nagyág, Romania
Field-hunting tip
Look in epithermal hydrothermal veins country — that is the host setting where sylvanite typically forms. If you start seeing gold, petzite, fluorite in float, you are in the right ground. Field specimens usually show a bladed crystals, skeletal growths, massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah — start trip planning there.
Common questions
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Find sylvanite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
