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.

Hardness

2.5-3

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareLillianite Group family

Eskimoite

Hardness: 2.5-3
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this eskimoite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch eskimoite with a known reference. Eskimoite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Eskimoite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Eskimoite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: lead-gray, steel-gray.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: acicular crystals, granular aggregates, massive.

Often confused with

Eskimoite vs. its common look-alikes, and how to tell them apart in the field.

mineral

Galena

Mohs 2.5

How to tell apart: Streak differs, so Eskimoite leaves black, Galena leaves lead-gray.

How to tell apart: Streak differs, so Eskimoite leaves black, Bismuthinite leaves lead-gray.

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: Ag₂Pb₃Bi₄S₉
Mohs hardness: 2.5-3
Density: 6.8-7.0 g/cm³
Colors: Lead-gray Steel-gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Acicular Crystals, Granular Aggregates, Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins, Pegmatites
Typical price: $50-300 per specimen

Where rockhounds find eskimoite

Classic worldwide localities

Ivigtut (Ivittuut), Greenland
Bolivia
Czech Republic

Field-hunting tip

Look in hydrothermal veins, pegmatites country, the host setting where eskimoite typically forms. If you start seeing galena, siderite, fluorite in float, you are in the right ground. Field specimens usually show a acicular crystals, granular aggregates, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify eskimoite?+

Mohs hardness is 2.5-3. It typically shows a metallic luster. The streak is black. Common colors include lead-gray, steel-gray.

Where is eskimoite found?+

Notable localities include Ivigtut (Ivittuut), Greenland; Bolivia; Czech Republic.

How much is eskimoite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is eskimoite safe to handle?+

It contains toxic constituents. Contains lead and bismuth; handle with care and avoid inhalation of dust or ingestion. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like eskimoite?+

Eskimoite is most often confused with Galena, Bismuthinite, Lillianite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with eskimoite?+

Eskimoite commonly co-occurs with Galena, Siderite, Fluorite, Cryolite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does eskimoite form in?+

Eskimoite typically forms in hydrothermal veins, pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is eskimoite used for?+

Eskimoite is used in collector.

Find eskimoite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.