Zaccagnaita-3R is a very rare speleotheme mineral discovered for the first time in 2012 in El Soplao cave in Cantabria (Spain).
This zaccagnaita is formed in caves, is of politipo 3R and is distinguished by its peculiar octahedral morphology and a zone of unknown fluorescence in the group to which the zaccagnaita belongs, that of the natural hydrotalcites. It is also much richer in aluminum than the hexagonal politipo (2H).
The origin of the zaccagnaita of El Soplao is related to the diagenesis of iron and manganese oxides (also rich in aluminum and zinc), which form the manganese stromatolites recently discovered in the cave of El Soplao.
The zaccagnaite discovered in Italy in 2001 has the formula Zn4Al2CO3 (OH) 12 · 3H2O and appears in white hexagonal crystals associated with calcite in cavities in Carrara marble of the Italian Alps and is thought to have been formed by hydrothermal alteration of sphalerite in an environment rich in aluminum. Of her there were only a few microscopic crystals that are not the same as those in the cave of El Soplao: Carrara is zaccagnaita-2H and the one in the cave is zaccagnaita-3R. It is named after Domenico Zaccagna (1851-1940), an Italian mineral collector. Note
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