campigliaite

{{Infobox mineral | name = Campigliaite | category = Copper oxysalt mineral | image = Campigliaite.jpg | caption = | formula = Cu4Mn(SO4)2(OH)6·4H2O | IMAsymbol=Cpg | strunz = 7.DD.30 | system = Monoclinic | class = Spheroidal (2) (same H-M symbol) | symmetry = C2 | unit cell = a = 21.7 Å, b = 6.09 Å, c = 11.24 Å; β = 100.3°; Z = 4 | color = Pale blue to pale greenish blue | habit = Typically as clusters or tufts of elongated or bladed crystals | twinning = Polysynthetic, with {100} as twin plane, ubiquitous | cleavage = Perfect on {100} | fracture = | tenacity = | mohs = | luster = Vitreous | polish = | refractive = nα = 1.589 nβ = 1.645 nγ = 1.659 | opticalprop = Biaxial (−) | birefringence = δ = 0.070 | 2V = 52° measured | dispersion = r 4Mn(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.

==History== S. Menchetti and C. Sabelli discovered campigliaite in one of the side tunnels of the Temperino Mine in Campiglia Marittima, Tuscany, Italy. The new mineral was named after its type locality and was approved by the Commission of New Minerals and Mineral Names, International Mineralogical Association.