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. Chalcopyrite leaves a greenish-black streak.
- 3Read the lusterHold the specimen under a strong light. Chalcopyrite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: brass-yellow, iridescent, gold.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: tetrahedral crystals, massive, botryoidal.
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); streak differs, so Chalcopyrite leaves greenish-black, Pyrite leaves greenish-black to brownish-black.
How to tell apart: Streak differs, so Chalcopyrite leaves greenish-black, Bornite leaves greyish black.
How to tell apart: Streak differs, so Chalcopyrite leaves greenish-black, Pyrrhotite leaves dark grey to 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
- Streak
- Greenish-black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Tetrahedral Crystals, Massive, Botryoidal
- Cleavage
- Indistinct
- Rarity
- Common
- Uses
- Ore, Collector, Specimen
- Host rock
- Hydrothermal Veins, Igneous, Metamorphic, And Sedimentary Deposits
- Typical price
- $5-50 thumbnail, $20-200 cabinet
Where rockhounds find chalcopyrite
118 mapped spotsClassic worldwide localities
- Chuquicamata, Chile
- Mount Lyell, Australia
- Kennecott, USA
- Rio Tinto, Spain
- Dzhezkazgan, Kazakhstan
U.S. states with chalcopyrite
Each link opens a state-specific list of mapped rockhounding spots that produce chalcopyrite.
- Utah27 spots
- Missouri14 spots
- New Mexico7 spots
- Massachusetts6 spots
- North Carolina6 spots
- Pennsylvania5 spots
- Virginia5 spots
Field-hunting tip
Look in hydrothermal veins, igneous, metamorphic, and sedimentary deposits country, the host setting where chalcopyrite typically forms. If you start seeing pyrite, sphalerite, galena in float, you are in the right ground. Field specimens usually show a tetrahedral crystals, massive, botryoidal habit, so 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.
Common questions
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Find chalcopyrite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
