Dioptase with Zincian Dolomite
Tsumeb Mine, Tsumeb, Namibia
Cabinet, 10.0 x 7.2 x 4.1 cm
Ex. Jack Halpern; Marshall Sussman

Tsumeb is most famous for its combinations of species and this is a dramatic, three-dimensional sparkling plate of the most deep and lustrous green dioptase you can imagine, lovingly carpeted by tiny sparkling sugary crystals of dolomite. The dolomites look like white sugar dropped on the dioptase, and have a slight tinge of pastel blue color, characteristic of a zinc content at some few parts per million. At a certain threshold of zinc concentration, zincian dolomite becomes the species minrecordite - and they DO look exactly like this in fact. We had this analyzed, therefore, but it falls just below the threshold to be considered the more rarified species. I suspect others, labelled as minrecordite, are equally not and are probably mostly mislabeled out there (the difference between quantitative and qualitative analyses by an expert lab is likely responsible for this, as it is easy to show the zinc is there but much harder to quantify it and determine if this is enough to make it a new species). This is nevertheless a dramatic dioptase, from a very special style, seldom seen. The accent of the contrasting dolomites really enhances the color of the green, and the hillocky shape. From the first Tsumeb collection of Marshall and Charlotte Sussman, and on the back of their label it notes that this was purchased in 1976 (by Marshall).