Haycockite is a rare copper-iron sulfide that typically occurs as microscopic exsolution lamellae within chalcopyrite. It is best identified through reflected light microscopy in polished sections due to its strong anisotropy and similar appearance to chalcopyrite in hand specimens.
Is this haycockite?
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 haycockite with a known reference. Haycockite 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. Haycockite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Haycockite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: brassy yellow, bronze.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: massive, anhedral grains.
Often confused with
Haycockite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside haycockite
Minerals reported to co-occur with haycockite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₄Fe₅S₈
- Mohs hardness
- 3.5-4
- Density
- 4.2 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Massive, Anhedral Grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Magmatic Sulfide Deposits
- Typical price
- $20-100 for small specimen
Where rockhounds find haycockite
Classic worldwide localities
- Haycock Mine, California, USA
- Stillwater Complex, Montana, USA
- Norilsk, Russia
- Sudbury, Ontario, Canada
Field-hunting tip
Look in magmatic sulfide deposits country — that is the host setting where haycockite typically forms. If you start seeing chalcopyrite, cubanite, pyrrhotite in float, you are in the right ground. Field specimens usually show a massive, anhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify haycockite?+
Where is haycockite found?+
How much is haycockite worth?+
What rocks look like haycockite?+
What minerals are found with haycockite?+
What kind of rock does haycockite form in?+
What is haycockite used for?+
Find haycockite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
