Kostovite is a rare gold-copper telluride mineral typically found in epithermal ore deposits. Collectors primarily seek it as an obscure species associated with copper-rich precious metal assemblages, where it often appears as inconspicuous metallic grains or small masses.
Is this kostovite?
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 kostovite with a known reference. Kostovite 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. Kostovite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Kostovite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: white, silver-white, pale brass-yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: granular to massive, rarely as tiny prismatic crystals.
Often confused with
Kostovite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Kostovite leaves black, Calaverite leaves yellowish-green.
How to tell apart: Streak differs — Kostovite leaves black, Krennerite leaves yellowish-grey.
How to tell apart: Streak differs — Kostovite leaves black, Sylvanite leaves gray.
Often found alongside kostovite
Minerals reported to co-occur with kostovite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- AuCuTe₄
- Mohs hardness
- 2
- Density
- 9.4-9.5 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Granular to Massive, Rarely as Tiny Prismatic Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Epithermal Gold-copper Deposits
- Typical price
- $50-500 depending on specimen size and matrix quality
Where rockhounds find kostovite
Classic worldwide localities
- Chelopech, Bulgaria
- Kochbulak, Uzbekistan
- Sapo Alegre, Brazil
Field-hunting tip
Look in epithermal gold-copper deposits country — that is the host setting where kostovite typically forms. If you start seeing pyrite, enargite, gold in float, you are in the right ground. Field specimens usually show a granular to massive, rarely as tiny prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find kostovite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
