10/25/2022
Diaspore is an aluminium-rich mineral, often with a colour-change effect (purplish pink in incandescent light and green in daylight equivalent) with strong pleochroism, perfect cleavage and moderate hardness (6 1/2 - 7 in the Mohs scale). It was found in Turkey after the massive bauxite (aluminium) deposits in the Mugla province began extraction operations in the 1970s, although official reports mention it later. It was then known to mineral collectors and occasionally cut as a collectors’ stone. In 2005 a greater gemmological interest arose after the discovery of significant gem-quality deposits that the marketing branch of the mining firm, Zultanite Gems LLC, marketed as “Zultanite”. The firm partners went apart and the mining company eventually re-branded the gem as “Csarite" after 2014, meaning that the same material is being marketed today by different companies under different trade names.
It used to be considered redundant to called it “colour-changing diaspore”, but non-phenomenal pink gem-quality material has been recently reported in Afghanistan.
In the photo, an exceptionally large and rare 121.65 ct diaspore cut by rudi wobito from a 2,150 ct rough from Turkey, demonstrating the very low yield of cutting this gemstone, as the size of the cut stone is a fraction of its rough (here about 5%) © Milenyum Minning.
