Pyrite is often mistaken for gold because of its light brass color and bright metallic luster, so it is also called "fool's gold".
Pyrite is a disulfide of iron. Pure pyrite contains 46.67% iron and 53.33% sulfur. Pyrite is generally used as a raw material for the production of sulfur and sulfuric acid, rather than as a raw material for refining iron, because there are better iron ores for refining iron. Pyrite is widely distributed and can be found in many ores and rocks, including coal. Generally in the shape of a brass-colored cube. Pyrite weathers into limonite or jarosite.
The chemical composition of pyrite is FeS2, and the crystal is a sulfide mineral of the equiaxed crystal system. The composition usually contains cobalt, nickel and selenium, and has a NaCl-type crystal structure. There are often complete crystal forms, including cubes, octahedrons, pentagonal dodecahedrons and polygonal shapes. There are stripes parallel to the crystal edges on the cubic crystal face, and the stripes on each crystal face are perpendicular to each other. The aggregates are in the form of dense blocks, granules or nodules. Light yellow (copper yellow) color, green-black streaks, strong metallic luster, opaque, no cleavage, jagged fracture. Mohs hardness is relatively high, reaching 6-6.5, and a knife cannot carve it. The proportion is 4.9-5.2. It is easily weathered into limonite under surface conditions.
How to distinguish "fool's gold" from real gold? As long as you scratch it on an unglazed white porcelain plate and see the streaks (i.e. the powder left on the white porcelain plate), you will be able to distinguish the authenticity from the fake. The streaks of gold ore are golden yellow, and the streaks of pyrite are green and black. In addition, when you weigh it with your hands, gold feels particularly heavy, because the specific gravity of natural gold is 15.6-18.3, while pyrite is only 4.9-5.2.
Pyrite is the most widely distributed sulfide mineral and can appear in all types of rocks. Pyrite is the main raw material for extracting sulfur and making sulfuric acid. It is also a very cheap ancient gemstone. In the era of Queen Victoria in England (1837-1901 AD), people liked to decorate with this kind of gemstone with special shape and ornamental value. In addition to being used for polishing gemstones, it can also be used as a base for jewelry, jade, and other handicrafts. The world's famous producing areas include Rio Tinto in Spain, the Czech Republic, Slovakia and the United States. China's pyrite reserves rank among the highest in the world. Famous producing areas include Yingde and Yunfu in Guangdong, Ma'anshan in Anhui, and Silver Factory in Gansu.
Theoretical composition (wB%): Fe 46.55, S 53.45. Co and Ni are often isomorphous in place of Fe, forming FeS2-CoS2 and FeS2-NiS2 series. As the content of Co and Ni instead of Fe increases, the unit cell increases, the hardness decreases, and the color becomes lighter. As, Se and Te can replace S. Often contains finely dispersed mixtures of Sb, Cu, Au, Ag, etc. There may also be trace elements such as Ge and In. Au often occurs in the cleavage plane or crystal lattice of pyrite as microscopic gold and ultramicroscopic gold.