Ikunolite is a rare bismuth sulfide mineral typically found as metallic, lead-gray foliated or lamellar masses. It is most commonly identified by its distinct cleavage and presence in bismuth-rich hydrothermal environments, often appearing alongside other bismuth-bearing sulfides.
Is this ikunolite?
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 ikunolite with a known reference. Ikunolite 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. 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: trigonal. Typical habit: lamellar, massive, foliated aggregates.
Often confused with
Ikunolite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ikunolite leaves dark gray, Bismuthinite leaves lead-gray.
How to tell apart: Streak differs, so Ikunolite leaves dark gray, Galena leaves lead-gray.
How to tell apart: Streak differs, so Ikunolite leaves dark gray, Tetradymite leaves pale steel-gray.
Often found alongside ikunolite
Minerals reported to co-occur with ikunolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Bi₄S₃
- Mohs hardness
- 2
- Density
- 7.8 g/cm³
- Colors
- Streak
- Dark gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Lamellar, massive, foliated aggregates
- Cleavage
- {0001}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a quartz vein (Ikuno mine, Japan)
Where rockhounds find ikunolite
Classic worldwide localities
- Ikuno (type locality) and Akenobe mines, Hyogo Prefecture, and at the Ashio mine, Tochigi Prefecture, Japan
- Kingsgate, New South Wales, Australia
- Falu mine, Falun, Kopparberg, Sweden
- Osikonmaki gold deposit, Rantasalmi, Finland
- Mullenbach uranium deposit, Black Forest, Germany
- Vysokogorsk tin deposit, Primorskiy Kray, and from the Kara-Oba Mo–W deposit, Bet-Pak-Dal Desert, central Kazakhstan
Field-hunting tip
Where it forms: In a quartz vein (Ikuno mine, Japan). If you start seeing ferberite, bismuth, bismuthinite in float, you are in the right ground. Typical habit: lamellar, massive, foliated aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ikunolite?+
Where is ikunolite found?+
Is ikunolite safe to handle?+
What rocks look like ikunolite?+
What minerals are found with ikunolite?+
What kind of rock does ikunolite form in?+
What is ikunolite used for?+
Find ikunolite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
