Chalcopyrite is the most important copper ore mineral, easily identified by its brass-yellow color and tendency to tarnish with iridescent blues, purples, and greens. It is commonly mistaken for pyrite, but it is softer and has a distinctive greenish-black streak. Collectors prize specimens for their bright metallic luster and frequent association with other sulfide minerals.
Is this chalcopyrite?
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 chalcopyrite with a known reference. Chalcopyrite 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. Streak: greenish black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: brass-yellow, iridescent, gold, honey yellow.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: druse, euhedral crystals, striated.
Often confused with
Chalcopyrite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Pyrite is the harder of the two (Mohs 6-6.5 vs. 3.5-4).
How to tell apart: Streak differs, so Chalcopyrite leaves greenish black, Bornite leaves pale grayish black.
How to tell apart: Streak differs, so Chalcopyrite leaves greenish black, Pyrrhotite leaves dark grayish black.
Often found alongside chalcopyrite
Minerals reported to co-occur with chalcopyrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CuFeS₂
- Mohs hardness
- 3.5-4
- Density
- 4.1-4.3 g/cm³
- Colors
- Streak
- Greenish black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Druse, euhedral crystals, striated
- Cleavage
- Poor on {011} and {111}
- Rarity
- Common
- Uses
- Ore, Collector, Specimen
- Host rock
- A primary mineral in hydrothermal veins, stockworks, disseminations, and massive replacements; an exsolution product in mafic igneous rocks; of sedimentary origin controlled by redox conditions
Where rockhounds find chalcopyrite
120 mapped spotsClassic worldwide localities
- Copper mines of Arizona, as at Bisbee, Cochise Co., USA
- Groundhog mine, Vanadium, Grant Co., New Mexico, USA
- New York, at the Rossie lead mines, St. Lawrence Co., USA
- French Creek, Chester Co., Pennsylvania, USA
- Cananea, Sonora, Mexico
- Huaron, Peru
U.S. states with chalcopyrite
Each link opens a state-specific list of mapped rockhounding spots that produce chalcopyrite.
- Utah27 spots
- Missouri14 spots
- New Mexico8 spots
- North Carolina7 spots
- Massachusetts6 spots
- Pennsylvania5 spots
- Virginia5 spots
Field-hunting tip
Where it forms: A primary mineral in hydrothermal veins, stockworks, disseminations, and massive replacements; an exsolution product in mafic igneous rocks; of sedimentary origin controlled by redox conditions. If you start seeing sphalerite, galena, tetrahedrite in float, you are in the right ground. Typical habit: druse, euhedral crystals, striated. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah, Missouri, New Mexico. Start trip planning there.
More chalcopyrite photos
Common questions
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Find chalcopyrite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
