Sugakiite is a rare copper-iron sulfide mineral typically found in intimate intergrowths within skarn-type ore deposits. It is primarily identified in polished sections via microscopic examination due to its extremely small grain size and similarity to other copper-iron sulfides.
Is this sugakiite?
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 sugakiite with a known reference. Sugakiite sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Sugakiite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Sugakiite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: bronze, yellow.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: granular, anhedral.
Often confused with
Sugakiite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Sugakiite leaves black, Chalcopyrite leaves greenish-black.
How to tell apart: Streak differs — Sugakiite leaves black, Pentlandite leaves light bronze-brown.
Often found alongside sugakiite
Minerals reported to co-occur with sugakiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CuFe₉S₈
- Mohs hardness
- 3.5-4
- Density
- 4.35 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Granular, Anhedral
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Skarn Deposits
- Typical price
- n/a
Where rockhounds find sugakiite
Classic worldwide localities
- Akagane mine, Iwate Prefecture, Japan
Field-hunting tip
Look in skarn deposits country — that is the host setting where sugakiite typically forms. If you start seeing chalcopyrite, pyrrhotite, cubanite in float, you are in the right ground. Field specimens usually show a granular, anhedral habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find sugakiite on the map
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