Clinoclase is a hydrous copper arsenate mineral, Cu3AsO4(OH)3. Clinoclase is a rare secondary copper mineral and forms acicular crystals in the fractured weathered zone above copper sulfide deposits. It occurs in vitreous, translucent dark blue to dark greenish blue colored crystals and botryoidal masses. The crystal system is monoclinic 2/m. It has a hardness of 2.5–3 and a relative density of 4.3. Associated minerals include malachite, olivenite, quartz, limonite, adamite, azurite, and brochantite among others.
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.
Chrysocolla ( KRIS-ə-KOL-ə) is a hydrous copper phyllosilicate mineral and mineraloid with the formula Cu
2 – xAl
x(H
2Si
2O
5)(OH)
4⋅nH
2O (x < 1) or (Cu, Al)
2H
2Si
2O
5(OH)
4⋅nH
2O).
Liroconite is a complex mineral: Hydrated copper aluminium arsenate hydroxide, with the formula Cu2Al[(OH)4|AsO4]·4(H2O). It is a vitreous monoclinic mineral, colored bright blue to green, often associated with malachite, azurite, olivenite, and clinoclase. It is quite soft, with a Mohs hardness of 2–2.5, and has a specific gravity of 2.9–3.0.
Tyrolite is a hydrous calcium copper arsenate carbonate mineral with the formula CaCu5(AsO4)2CO3(OH)4⋅6H2O. Tyrolite forms glassy, blue to green orthorhombic radial crystals and botryoidal masses. It has a Mohs hardness of 1.5–2.0 and a specific gravity of 3.1–3.2. It is translucent with refractive indices of nα = 1.694, nβ = 1.726, and nγ = 1.730.
Chloritoid is a silicate mineral of metamorphic origin. It is an iron magnesium manganese alumino-silicate hydroxide with formula (Fe, Mg, Mn)
2Al
4Si
2O
10(OH)
4. It occurs as greenish grey to black platy micaceous crystals and foliated masses. Its Mohs hardness is 6.5, unusually high for a platy mineral, and it has a specific gravity of 3.52 to 3.57. It typically occurs in phyllites, schists and marbles.
Sauconite is a complex phyllosilicate mineral of the smectite clay group, formula Na0.3Zn3(SiAl)4O10(OH)2·4H2O. It forms soft earthy bluish white to red-brown monoclinic crystals typically massive to micaceous in habit. It has a Mohs hardness of 1 to 2 and a specific gravity of 2.45. Optically it is biaxial positive with refractive index values of nα = 1.550 – 1.580, nβ = 1.590 – 1.620 and nγ = 1.590 – 1.620. It is found in vugs and seams in the oxidized zones of zinc and copper deposits. It occurs in association with hemimorphite, smithsonite, chrysocolla, coronadite and various iron oxides.
Fornacite is a rare lead, copper chromate arsenate hydroxide mineral with the formula: Pb2Cu(CrO4)(AsO4)(OH). It forms a series with the phosphate mineral vauquelinite. It forms variably green to yellow, translucent to transparent crystals in the monoclinic – prismatic crystal system. It has a Mohs hardness of 2.3 and a specific gravity of 6.27.
Djurleite is a copper sulfide mineral of secondary origin with formula Cu31S16 that crystallizes with monoclinic-prismatic symmetry. It is typically massive in form, but does at times develop thin tabular to prismatic crystals. It occurs with other supergene minerals such as chalcocite, covellite and digenite in the enriched zone of copper orebodies. It is a member of the chalcocite group, and very similar to chalcocite, Cu2S, in its composition and properties, but the two minerals can be distinguished from each other by x-ray powder diffraction. Intergrowths and transformations between djurleite, digenite and chalcocite are common. Many of the reported associations of digenite and djurleite, however, identified by powder diffraction, could be anilite and djurleite, as anilite transforms to digenite during grinding.
Plancheite is a hydrated copper silicate mineral with the formula Cu8Si8O22(OH)4•(H2O). It is closely related to shattuckite in structure and appearance, and the two minerals are often confused.
Lavendulan is an uncommon arsenate mineral in the lavendulan group. It is known for its characteristic intense electric blue colour. Lavendulan is very similar to Lemanskiite, the analogue trihydrate mineral, to the point of them being considered dimorphs. Lemanskiite is tetragonal, but lavendulan is monoclinic. Lavendulan has the same structure as sampleite, and the two minerals form a series. It is the calcium analogue of zdenĕkite and the arsenate analogue of sampleite.
Cornubite is a rare secondary copper arsenate mineral with formula: Cu5(AsO4)2(OH)4. It was first described for its discovery in 1958 in Wheal Carpenter, Gwinear, Cornwall, England, UK. The name is from Cornubia, the medieval Latin name for Cornwall. It is a dimorph of cornwallite, and the arsenic analogue of pseudomalachite.
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.
Tsumebite is a rare phosphate mineral named in 1912 after the locality where it was first found, the Tsumeb mine in Namibia, well known to mineral collectors for the wide range of minerals found there. Tsumebite is a compound phosphate and sulfate of lead and copper, with hydroxyl, formula Pb2Cu(PO4)(SO4)(OH). There is a similar mineral called arsentsumebite, where the phosphate group PO4 is replaced by the arsenate group AsO4, giving the formula Pb2Cu(AsO4)(SO4)(OH). Both minerals are members of the brackebuschite group.
Pearceite is one of the four so-called "ruby silvers", pearceite Cu(Ag,Cu)6Ag9As2S11, pyrargyrite Ag3SbS3, proustite Ag3AsS3 and miargyrite AgSbS2. It was discovered in 1896 and named after Dr Richard Pearce (1837–1927), a Cornish–American chemist and metallurgist from Denver, Colorado.
Strashimirite is a rare monoclinic mineral containing arsenic, copper, hydrogen, and oxygen. It has the chemical formula Cu8(AsO4)4(OH)4·5(H2O).
Cornwallite is an uncommon copper arsenate mineral with formula Cu5(AsO4)2(OH)4. It forms a series with the phosphate pseudomalachite and is a dimorph of the triclinic cornubite. It is a green monoclinic mineral which forms as radial to fibrous encrustations.
Carminite (PbFe3+2(AsO4)2(OH)2) is an anhydrous arsenate mineral containing hydroxyl. It is a rare secondary mineral that is structurally related to palermoite (Li2SrAl4(PO4)4(OH)4). Sewardite (CaFe3+2(AsO4)2(OH)2) is an analogue of carminite, with calcium in sewardite in place of the lead in carminite. Mawbyite is a dimorph (same formula, different structure) of carminite; mawbyite is monoclinic and carminite is orthorhombic. It has a molar mass of 639.87 g. It was discovered in 1850 and named for the characteristic carmine colour.
Serpierite (Ca(Cu,Zn)4(SO4)2(OH)6·3H2O) is a rare, sky-blue coloured hydrated sulfate mineral, often found as a post-mining product. It is a member of the devilline group, which has members aldridgeite (Cd,Ca)(Cu,Zn)4(SO4)2(OH)6·3H2O, campigliaite Cu4Mn2+(SO4)2(OH)6·4H2O, devilline CaCu4(SO4)2(OH)6·3H2O, kobyashevite Cu5(SO4)2(OH)6·4H2O, lautenthalite PbCu4(SO4)2(OH)6·3H2O and an unnamed dimorph of devilline. It is the calcium analogue of aldridgeite and it is dimorphous with orthoserpierite CaCu4(SO4)2(OH)6·3H2O.
Mottramite is an orthorhombic anhydrous vanadate hydroxide mineral, PbCu(VO4)(OH), at the copper end of the descloizite subgroup. It was formerly called cuprodescloizite or psittacinite (this mineral characterized in 1868 by Frederick Augustus Genth). Duhamelite is a calcium- and bismuth-bearing variety of mottramite, typically with acicular habit.
