Detailed information
Species
Hemimorphite
Dimensions
103 x 95 x 33
mm
Weight
284 g
Locality
Sa Duchessa Mine, Oridda Domusnovas, Carbonia-Iglesias Province Sardinia, Italy
Condition
No recorded repairs
The colour of this Sa Duchessa mine Hemimorphite is insane. Pure Hemimorphite, or zinc silicate hydroxide hydrate, should be colourless, but natural impurities provide a range of colour: in this case copper. Cabinet in size, this display piece is really eye-catching, the blue being much more saturated and intense than other classic world localities for blue Hemimorphite - like the Caldbeck Fells in England. A feature very typical of Sa Duchessa mine is the prominent colour banding seen is cross-section through the layers and the glossy lustre on the outermost botryoidal layer. There are a couple of small areas where the surface has been contacted, but overall, this is an extremely high quality old-time survivor from this classic European Hemimorphite occurrence, with a very large display area. The matrix is classic porous rusty orange gossan. Sa Duchessa zinc mine opened in 1870 and was quite productive during the 1870s. By the 1930s clear signs of decline were evident and despite a shift in emphasis to copper the mine never really got going again, eventually being closed in about 1970. Most of the best Hemimorphite specimens date to the 1960s, or earlier. Ex Franz Lammer collection (1914-1997).