Difference Between Pyrite and Chalcopyrite

Key Difference – Pyrite vs Chalcopyrite

Pyrite and chalcopyrite are both sulfide minerals, but their chemical composition is different. The key difference between pyrite and chalcopyrite is that pyrite contains iron sulfide (FeS2) whereas chalcopyrite contains sulfides of copper and iron (CuFeS2). Despite having similar names and slightly similar chemical formula, their chemical properties are different, and they are used in different industrial applications.

What is Pyrite?

Pyrite is a sulfide mineral containing iron (Fe) and sulfur (S) as structural elements. Its chemical formula is FeS2. It is also known as iron pyrite and “fool’s gold” due to its pale-brass yellow color. In the ancient days, people misunderstood pyrite as gold since it possesses a yellowish metallic luster similar to gold. It is one of most commonly found sulfide minerals, and also it can be found with other oxides in quartz veins, sedimentary rocks, and metamorphic rocks. Sometimes, it is found in small quantities of gold too. The word “pyrite” is derived from the Greek word “pyr”, which has the meaning “fire”. It got this name since pyrite can create sparks when it hits another mineral or metal.

Difference Between Pyrite and Chalcopyrite

What is Chalcopyrite?

Chalcopyrite is a copper iron sulfide mineral, and its chemical formula is CuFeS2. This mineral is naturally presented in a variety of ores; from huge masses to irregular veins and it is considered as the most important copper ore. Chalcopyrite oxidizes to several types of oxides, hydroxides, and sulfates when it is exposed to the air. Some examples include bornite (Cu5FeS4), chalcocite (Cu2S), covellite (CuS), digenite (Cu9S5), malachite Cu2CO3(OH)2, and rare oxides such as cuprite (Cu2O). But, it is very rarely found with native copper (It is the uncombined form of copper which occurs as a natural mineral).

Key Difference - Pyrite vs Chalcopyrite

What is the difference between Pyrite and Chalcopyrite?

Appearance of Pyrite and Chalcopyrite:

Pyrite: It has a pale brass yellowish color with a metallic luster.

Chalcopyrite: It is brassy to golden yellowish in color.

Chemical Composition of Pyrite and Chalcopyrite:

Pyrite: Pyrite has the chemical formula FeS2, and it is an iron sulfide mineral.

Chalcopyrite: The chemical formula of chalcopyrite is CuFeS2. It is a copper iron sulfide mineral which has a greater economic value since it is the most important copper ore on Earth.

Extent of Oxidization of Pyrite and Chalcopyrite:

Pyrite: In general, finely crystallized pyrite minerals are relatively stable, and those are formed from sedimentary concentrations decomposes (The process of separation of a material into its constituents by a chemical reaction) quickly. Pyrite oxidizes slowly in a moist environment and discharges sulfuric acid that is formed during the process.

Chalcopyrite: In the exposure to the air, chalcopyrite forms not only one compound but several types of oxides, hydroxides, and sulfates. Examples of some sulfates are; bornite (Cu5FeS4), chalcocite (Cu2S), covellite (CuS), digenite (Cu9S5). Malachite Cu2CO3(OH)2 is an example for a hydroxide and cuprite (Cu2O) is a rarely produced oxide. Chalcopyrite very rarely oxidizes to native copper.

Uses of Pyrite and Chalcopyrite:

Pyrite: Pyrite is used to produce sulfur dioxide for the paper manufacturing process. It also uses to produce sulfuric acid by thermally decomposing pyrite (FeS2) into iron (II) sulfide (FeS) and then to elemental sulfur at 540 °C; at 1 atm.

Chalcopyrite: In industrial scale, chalcopyrite is mainly used as the main copper source. Even it mainly has only one usage; it is considered as very important since copper wires are used in nearly all electronic devices in the modern society.


Image Courtesy:

1. Pyrite from Ampliaci, a Victoria Mine, Navaj, La Rioja, Spain2 By JJ Harrison ([email protected]) – Own work, [CC BY-SA 3.0] via Wikimedia Commons

2. Pyrite-Chalcopyrite-Sphalerite-46860 By Rob Lavinsky, [CC BY-SA 3.0], via Wikimedia Commons