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Pyrite cubic crystals on marl from Navajún, La Rioja, Spain (size: 95 by 78 millimetres [3.7 by 3.1 in], 512 grams [18.1 oz]; main crystal: 31 millimetres [1.2 in] on edge) Pyrite's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold , hence the well-known nickname of fool's gold .
Marcasite jewellery is jewellery made using cut and polished pieces of pyrite (fool's gold) as gemstone, and not, as the name suggests, from marcasite. [1] Both pyrite and marcasite are chemically iron sulfide, but differ in their crystal structures, giving them different physical properties. Pyrite is more stable and less brittle than marcasite.
Mackinawite is an iron nickel sulfide mineral with the chemical formula (Fe,Ni) 1+x S (where x = 0 to 0.11). The mineral crystallizes in the tetragonal crystal system and has been described as a distorted, close packed, cubic array of S atoms with some of the gaps filled with Fe. [6]
Pyrrhotite (pyrrhos in Greek meaning "flame-coloured") is an iron sulfide mineral with the formula Fe (1-x) S (x = 0 to 0.125). It is a nonstoichiometric variant of FeS, the mineral known as troilite. Pyrrhotite is also called magnetic pyrite, because the color is similar to pyrite and it is
Lapis lazuli (UK: / ˌ l æ p ɪ s ˈ l æ z (j) ʊ l i, ˈ l æ ʒ ʊ-,-ˌ l i /; US: / ˈ l æ z (j) ə l i, ˈ l æ ʒ ə-,-ˌ l i /), or lapis for short, is a deep-blue metamorphic rock used as a semi-precious stone that has been prized since antiquity for its intense color.
[1] [2] The group is named for its most common member, pyrite (fool's gold), which is sometimes explicitly distinguished from the group's other members as iron pyrite . Pyrrhotite (magnetic pyrite) is magnetic, and is composed of iron and sulfur , but it has a different structure and is not in the pyrite group.
Lazurite is a product of contact metamorphism of limestone and is typically associated with calcite, pyrite, diopside, humite, forsterite, hauyne and muscovite. [ 2 ] Other blue minerals, such as the carbonate mineral, azurite , and the phosphate mineral, lazulite , may be confused with lazurite, but are easily distinguished with careful ...
Thus, the ideal formula one would expect for a spinel like carrollite is Cu 2+ Co 3+ 2 S 2− 4, but as in the case of copper sulfides in general the oxidation state of the copper atom is 1+, not 2+. An assignment of valences as Cu + Co 3+ 2 S 1.75− 4 is more appropriate; this was confirmed in a study of 2009. [ 11 ]