Jaskólskiite is an extremely rare lead-copper-antimony sulfosalt that typically presents as fine, acicular needles or small prismatic crystals within hydrothermal veins. It is a prized specimen for advanced collectors due to its scarcity and distinct lead-gray metallic luster. Identification often requires analytical methods like X-ray diffraction or electron microprobe due to its similarity to other lead-sulfosalts.
Is this jaskólskiite?
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 jaskólskiite with a known reference. Jaskólskiite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: dark gray.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: lead gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: aggregates.
Often confused with
Jaskólskiite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Jaskólskiite is noticeably harder (Mohs 4 vs. 2.5-3); streak differs, so Jaskólskiite leaves dark gray, Cosalite leaves black.
How to tell apart: Jaskólskiite is noticeably harder (Mohs 4 vs. 2.5-2.75); streak differs, so Jaskólskiite leaves dark gray, Galena leaves lead-gray.
How to tell apart: Jaskólskiite is noticeably harder (Mohs 4 vs. 2.5-3); streak differs, so Jaskólskiite leaves dark gray, Bournonite leaves steel-gray to iron-black; luster reads metallic on Jaskólskiite and brilliant to dull on Bournonite.
Often found alongside jaskólskiite
Minerals reported to co-occur with jaskólskiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₀.₁₅Pb₂.₁₅(Sb,Bi)₁.₈₅S₅
- Mohs hardness
- 4
- Density
- 6.5 g/cm³
- Colors
- Streak
- Dark gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Aggregates
- Cleavage
- Good on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In aggregates of sulfosalts and sulfides in polymetallic hydrothermal veins
Where rockhounds find jaskólskiite
Classic worldwide localities
- Vena mines, near Askersund, Örebro, Sweden (type locality)
- Zlata Bana deposit, Slanske vrchy Mountains, Slovakia
- Apollo mine, near Raubach, Siegerland, Germany
- Srednegolgotaiskoe gold deposit, eastern Transbaikalia, Siberia, Russia
- Izok Lake, Northwest Territories, Canada
Field-hunting tip
Where it forms: In aggregates of sulfosalts and sulfides in polymetallic hydrothermal veins. If you start seeing galena, pyrrhotite, chalcopyrite in float, you are in the right ground. Typical habit: aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify jaskólskiite?+
Where is jaskólskiite found?+
Is jaskólskiite safe to handle?+
What rocks look like jaskólskiite?+
What minerals are found with jaskólskiite?+
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Find jaskólskiite on the map
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