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Carraraite is a relatively new mineral of the ettringite-thaumasite group. It is found in the Alpuan Alps in Italy, specifically the Carrara region from where it gets its name. It occurs naturally as a hydrothermal alteration product of certain sulfides within calcite veins of Carrara marble. This marble is quite famous for the many rare minerals that form within its cavities.

Carraraite has a hexagonal crystal system and its only crystals are no larger than 0.06 millimeters across. Due to its very small size, much of the crystal and chemical data collected and analyzed for carraraite could only be obtained from X-ray diffraction and energy dispersive spectrometry

Discovery and occurrence
Carraraite was first found at Gioia quarry in Colonnata valley within calcite vein cavities in the marble. It occurs as hydrothermal alteration product of copper-vanadium sulfides such as sulvanite and colusite. Carraraite crystals are milky or transparent in color with a vitreous luster. One of the few other minerals found in the Carrara region with germanium, colusite was found to have a 1.3 percent weight of germanium content. The Carrara marble quarries where carraraite is found is also home to a significant amount of other rare minerals within cavities in the marble. These cavities are abundant in definite levels, specifically dolomitic layers that underwent deformation during metamorphism. In these cavities, there are over 100 minerals that form similarly to carraraite; the most common are quartz, gypsum, fluorite, and dolomite.

The Carrara marble quarries of the Carrara basin in the Apuan Alps contain some of the finest marble in the world. The marble is an extremely pure metamorphic limestone of the Liassic age. Carrara marble has been quarried for more than 2000 years and has been extremely popular due to its wide range of marble types (veined, statuary, brecciated, bardiglio, flowered, etc.). Carraraite was named after the Carrara marble quarries of the Apuan Alps north of Tuscany, Italy.

Structure
A diffractometer was used to determine the precise cell parameters of the hexagonal crystal structure. Those parameters are: a = 11.056 (3) Å, c = 10.629 (6) Å. The starting parameters for determining space group were derived from structural results of the mineral Thaumasite. During determination of the crystal structure of thaumasite, [Si(OH)6]2- ions were shown to be present. This was the first known evidence of a six-coordination of Silica by hydroxyl. Since thaumasite and carraraite are so similar in their chemical formulas, the structure of carraraite must include [Ge(OH)6]2- ions. There have only been a few minerals in which six-coordination of Germanium by hydroxyl has occurred. The bond lengths of some bonds in carraraite correspond to bond lengths in the mineral fleischerite, specifically the bond between the germanium and hydroxyl atoms. The distances for the Ge-OH bond in carraraite and fleischerite are 1.869 Å and 1.900 Å, respectively. Another mineral, jouravskite, even more closely structured, has a Ge-OH bond length of 1.88. The Ca-OH bond lengths for carraraite range between 2.42 and 2.52 Å while those for jouravskite range between 2.39 and 2.45 Å.