Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium, with the chemical formula CuAl6(PO4)4(OH)8·4H2O. It is rare and valuable in finer grades and has been prized as a gemstone for millennia due to its hue.
Azurite or Azure spar is a soft, deep-blue copper mineral produced by weathering of copper ore deposits. During the early 19th century, it was also known as chessylite, after the type locality at Chessy-les-Mines near Lyon, France. The mineral, a basic carbonate with the chemical formula Cu3(CO3)2(OH)2, has been known since ancient times, and was mentioned in Pliny the Elder's Natural History under the Greek name kuanos (κυανός: "deep blue," root of English cyan) and the Latin name caeruleum. Copper (Cu2+) gives it its blue color.
Chalcanthite (from Ancient Greek χάλκανθον (khálkanthon), from χαλκός (khalkós) 'copper' and ἄνθος (ánthos) 'flower, bloom') is a richly colored blue-green water-soluble sulfate mineral CuSO4·5H2O. It is commonly found in the late-stage oxidation zones of copper deposits. Due to its ready solubility, chalcanthite is more common in arid regions.
Aurichalcite is a carbonate mineral, usually found as a secondary mineral in copper and zinc deposits. Its chemical formula is (Zn,Cu)5(CO3)2(OH)6. The zinc to copper ratio is about 5:4. Copper (Cu2+) gives aurichalcite its green-blue colors.
Cuprite is an oxide mineral composed of copper(I) oxide Cu2O, and is a minor ore of copper.
Dioptase is an intense emerald-green to bluish-green mineral that is cyclosilicate of copper. It is transparent to translucent. Its luster is vitreous to sub-adamantine. Its formula is Cu6Si6O18·6H2O, also reported as CuSiO2(OH)2. It has a Mohs hardness of 5, the same as tooth enamel. Its specific gravity is 3.28–3.35, and it has two perfect and one very good cleavage directions. Additionally, dioptase is very fragile, and specimens must be handled with great care. It is a trigonal mineral, forming six-sided crystals that are terminated by rhombohedra.
Vivianite (Fe(II)
3(PO
4)
2·8H
2O) is a hydrated iron(II) phosphate mineral found in a number of geological environments. Small amounts of manganese Mn2+, magnesium Mg2+, and calcium Ca2+ may substitute for iron Fe2+ in its structure. Pure vivianite is colorless, but the mineral oxidizes very easily, changing the color, and it is usually found as deep blue to deep bluish green prismatic to flattened crystals. Vivianite crystals are often found inside fossil shells, such as those of bivalves and gastropods, or attached to fossil bone. Vivianite can also appear on the iron coffins or on the corpses of humans as a result of a chemical reaction of the decomposing body with the iron enclosure.
Atacamite is a copper halide mineral: a copper(II) chloride hydroxide with formula Cu2Cl(OH)3. It was first described for deposits in the Atacama Desert of Chile in 1802 by Dmitri de Gallitzin. The Atacama Desert is also the namesake of the mineral.
Adamite is a zinc arsenate hydroxide mineral, Zn2AsO4OH. It is a mineral that typically occurs in the oxidized or weathered zone above zinc ore occurrences. Pure adamite is colorless, but usually it possess yellow color due to Fe compounds admixture. Tints of green also occur and are connected with copper substitutions in the mineral structure. Olivenite is a copper arsenate that is isostructural with adamite and there is considerable substitution between zinc and copper resulting in an intermediate called cuproadamite. Zincolivenite is a recently discovered mineral being an intermediate mineral with formula CuZn(AsO4)(OH). Manganese, cobalt, and nickel also substitute in the structure. An analogous zinc phosphate, tarbuttite, is known.
Brochantite is a sulfate mineral, one of a number of cupric sulfates. Its chemical formula is Cu4SO4(OH)6. Formed in arid climates or in rapidly oxidizing copper sulfide deposits, it was named by Armand Lévy for his fellow Frenchman, geologist and mineralogist A. J. M. Brochant de Villiers.
Linarite is a somewhat rare, crystalline mineral that is known among mineral collectors for its unusually intense, pure blue color. It is formed by the oxidation of galena and chalcopyrite and other copper sulfides. It is a combined copper lead sulfate hydroxide with formula PbCuSO4(OH)2. Linarite occurs as monoclinic prismatic to tabular crystals and irregular masses. It is easily confused with azurite, but does not react with dilute hydrochloric acid as azurite does. It has a Mohs hardness of 2.5 and a specific gravity of 5.3 – 5.5.
Crocoite is a mineral consisting of lead chromate, PbCrO4, and crystallizing in the monoclinic crystal system. It is identical in composition with the artificial product chrome yellow used as a paint pigment.
Ajoite is a hydrated sodium potassium copper aluminium silicate hydroxide mineral. Ajoite has the chemical formula (Na,K)Cu7AlSi9O24(OH)6·3H2O, and minor Mn, Fe and Ca are usually also present in the structure. Ajoite is used as a minor ore of copper.
Chalcophyllite is a rare secondary copper arsenate mineral occurring in the oxidized zones of some arsenic-bearing copper deposits. It was first described from material collected in Germany. At one time chalcophyllite from Wheal Tamar in Cornwall, England, was called tamarite, but this name is now discredited. At Wheal Gorland a specimen exhibiting partial replacement of liriconite, Cu
2Al(AsO
4)(OH)
4·(4H
2O), by chalcophyllite has been found. The mineral is named from the Greek, chalco "copper" and fyllon, "leaf", in allusion to its composition and platy structure. It is a classic Cornish mineral that can be confused with tabular spangolite.
Boleite is a complex halide mineral with formula: KPb26Ag9Cu24(OH)48Cl62. It was first described in 1891 as an oxychloride mineral. It is an isometric mineral which forms in deep-blue cubes. There are numerous minerals related to boleite, such as pseudoboleite, cumengite, and diaboleite, and these all have the same complex crystal structure. They all contain bright-blue cubic forms and are formed in altered zones of lead and copper deposits, produced during the reaction of chloride bearing solutions with primary sulfide minerals.
Ashburtonite is a rare lead copper silicate-bicarbonate mineral with formula: HPb4Cu2+4Si4O12(HCO3)4(OH)4Cl.
Campigliaite is a copper and manganese sulfate mineral with a chemical formula of Cu4Mn(SO4)2(OH)6·4H2O. It has a chemical formula and also a crystal structure similar to niedermayrite, with Cd(II) cation replacing by Mn(II). The formation of campigliaite is related to the oxidation of sulfide minerals to form sulfate solutions with ilvaite associated with the presence of manganese. Campigliaite is a rare secondary mineral formed when metallic sulfide skarn deposits are oxidized. While there are several related associations, there is no abundant source for this mineral due to its rare process of formation. Based on its crystallographic data and chemical formula, campigliaite is placed in the devillite group and considered the manganese analogue of devillite. Campigliaite belongs to the copper oxysalt minerals as well followed by the subgroup M=M-T sheets. The infinite sheet structures that campigliaite has are characterized by strongly bonded polyhedral sheets, which are linked in the third dimension by weaker hydrogen bonds.
Plumbogummite is a rare secondary lead phosphate mineral, belonging to the alunite supergroup of minerals, crandallite subgroup. Some other members of this subgroup are:
Langite is a rare hydrated copper sulfate mineral, with hydroxyl, found almost exclusively in druses of small crystals. It is formed from the oxidation of copper sulfides, and was first described in specimens from Cornwall, United Kingdom. It is dimorphous with wroewolfeite. Langite was discovered in 1864 and named after the physicist and crystallographer Viktor von Lang (1838–1921), who was Professor of Physics at the University of Vienna, Austria.
Queitite is a lead zinc silicate sulphate that was named after the mineral dealer Clive S. Queit, who collected the first specimens. It got approved by the IMA in 1979, and it is an extremely rare secondary mineral.
