Chalcopyrite
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Chalcopyrite is named from the Greek word chalkos for copper and Pyrite, hence "Copper Pyrite."

Discovered in 1747;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

CuFeS₂

Copper Iron Sulfide

Molecular Weight:

521.21 gm

Composition:

Iron

30.43 %

Fe

Copper

34.63 %

Cu

Sulfur

34.94 %

S

100.00 %

Classification

Mineral Classification:

Sulfides

Strunz 8th Ed. ID:

2/C.03-10

Nickel-Strunz 10th Ed. ID:

2.CB.10

2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
C : Metal Sulfides, M: S = 1: 1 (and similar)
B : With Zn, Fe, Cu, Ag, etc.

Related to:

Chalcopyrite Group. Chalcopyrite - Eskebornite Series.

Members of Group:

Chalcopyrite Group: Chalcopyrite, Eskebornite, Gallite, Laforêtite, Lenaite, Roquesite

Varieties:

Auriferous Chalcopyrite, Blister Copper, Stannian Chalcopyrite

Synonyms:

Chalkopyrite, Copper Pyrites, Cupropyrite, Gelferz, Kopparglasertz, Kupfereisenerz, Kupfereisenerzkies, Kupferkis, Towanite, Yellow Copper, Yellow Copper Ore, Yellow Pyrite

Crystal Data

Crystallography:

Tetragonal - Scalenohedral

Crystal Habit:

Equant, tetrahedral-shaped crystals, may be modified by scalenohedral faces, to as large as 10 cm. Sphenoidal faces typically large, dull in luster and striated. Commonly massive, compact; can be botryoidal.

Twinning:

Twin plane {112}, composition surface commonly {112}; twin plane {012}; also by rotation about {001} with composition plane {110}, producing penetration twins.

Physical Properties

Cleavage:

Poor/Indistinct on {011}, Poor/Indistinct on {111}

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Moh's Hardness:

3.5 - 4.0

Density:

4.1 - 4.3 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Magnetic after heating.

Optical Properties

Color:

Brass Yellow, honey Yellow; may be tarnished and iridescent

Transparency:

Opaque

Luster:

Metallic

Refractive Index:

R1–R2: (400) 16.0–17.3, (420) 20.0–21.3, (440) 24.8–26.1, (460) 30.2–31.4, (480) 34.9–35.9, (500) 38.9–39.9, (520) 41.9–42.7, (540) 44.0–44.9, (560) 45.4–46.4, (580) 46.6–47.6, (600) 47.1–48.3, (620) 47.5–4.86, (640) 47.6–48.7, (660) 47.6–48.7, (680) 47.6–48.6, (700) 47.6–48.6

Birefringence:

None; Opaque

Dispersion:

None

Pleochroism:

None

Anisotrophism:

Weak

Occurances

Geological Setting:

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.

Common Associations:

Galena, Pyrite, Sphalerite, Tetrahedrite, many Copper Sulfides

Common Impurities:

Ag, Au, In, Tl, Se, Te

Type Locality:

Unknown

Year Discovered:

1747

View mineral photos:

Chalcopyrite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Chalcopyrite is a fairly common mineral that is often confused with Pyrite (FeS2). Chalcopyrite typically has a brass yellow color and my be tarnished and iridescent. It is one of the minerals sometimes refered to as "Fool's Gold" because of its bright golden color. Its widespread distribution and large quantities make Chalcopyrite a major ore of copper even though its yeild of only 25% is rather low compared to other copper minerals such as Chalcocite (67%); Cuprite (67%); Bornite (50%); and Covellite (50%).

Chalcopyrite is found in many localities worldwide. Notable occurances include Rouyn district, Quebec, Canada; Huaron, Peru; the Nababiep Mine, Cape Province, South Africa; and Bisbee, Cochise County, Arizona, USA.
 

  
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