Eskimoite is a rare sulfosalt mineral primarily known from its type locality in the cryolite deposits of Ivigtut, Greenland. It typically occurs as small, needle-like acicular crystals or massive metallic aggregates within hydrothermal environments associated with lead and bismuth sulfides.
Is this eskimoite?
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 eskimoite with a known reference. Eskimoite 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: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: black, gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: granular, lamellar.
Often confused with
Eskimoite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Eskimoite is noticeably harder (Mohs 4 vs. 2.5-2.75); streak differs, so Eskimoite leaves black, Galena leaves lead-gray.
How to tell apart: Eskimoite is noticeably harder (Mohs 4 vs. 2-2.5); streak differs, so Eskimoite leaves black, Bismuthinite leaves lead-gray.
How to tell apart: Eskimoite is noticeably harder (Mohs 4 vs. 2-3).
Often found alongside eskimoite
Minerals reported to co-occur with eskimoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ag₇Pb₁₀Bi₁₅S₃₆
- Mohs hardness
- 4
- Density
- 7.1 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Granular, lamellar
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a cryolite deposit (Ivigtut, Greenland)
Where rockhounds find eskimoite
Classic worldwide localities
- Ivigtut cryolite deposit, southwestern Greenland (type locality)
- Kochbulak gold deposit, Chatkal-Kuramin Mountains, eastern Uzbekistan
- La Roche-Balue quarry, west of Nantes, Loire Atlantique, France
- Rauriser Goldberg, Salzburg, Austria
Field-hunting tip
Where it forms: In a cryolite deposit (Ivigtut, Greenland). If you start seeing berryite, aikinite, galena in float, you are in the right ground. Typical habit: granular, lamellar. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify eskimoite?+
Where is eskimoite found?+
Is eskimoite safe to handle?+
What rocks look like eskimoite?+
What minerals are found with eskimoite?+
What kind of rock does eskimoite form in?+
What is eskimoite used for?+
Find eskimoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
