Empressite is a rare silver telluride mineral often found as granular masses in hydrothermal gold-telluride deposits. It is best identified by its metallic luster, black streak, and association with other telluride minerals, though it is frequently intergrown with or replaced by hessite.
Is this empressite?
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 empressite with a known reference. Empressite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Empressite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Empressite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: white, pale brass yellow, gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: massive, granular, rarely as small crystals.
Often confused with
Empressite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Empressite is noticeably harder (Mohs 3.5 vs. 1.5-2); streak differs — Empressite leaves black, Sylvanite leaves gray.
How to tell apart: Streak differs — Empressite leaves black, Petzite leaves iron-black.
Often found alongside empressite
Minerals reported to co-occur with empressite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- AgTe
- Mohs hardness
- 3.5
- Density
- 7.5 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Massive, Granular, Rarely as Small Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Epithermal Hydrothermal Veins
- Typical price
- $50-300 per specimen
Where rockhounds find empressite
Classic worldwide localities
- Empress Josephine mine, Colorado, USA
- Gueriguina, Romania
- Tilly Foster mine, New York, USA
- Kalgoorlie, Australia
Field-hunting tip
Look in epithermal hydrothermal veins country — that is the host setting where empressite typically forms. If you start seeing tellurium, gold, hessite in float, you are in the right ground. Field specimens usually show a massive, granular, rarely as small crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find empressite on the map
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