Blue sapphires from Kashmir sapphire are considered fine enough by the auction houses to advertise their place of origin (as with Myanmar blue sapphire and ruby, Colombian emerald). Accounts of the areas and its mines are very hard to find, the best being C.S. Middlemiss, Mineral Survey Reports, Jammu and Kashmir Government, Precious and Semi-Precious Gemstones of Jammu and Kashmir, 1931 [this description taken from the cover]. The report is followed by a photograph and six folding sketch maps and is #4464 in the Sinkankas bibliography mentioned passim in this book. This is the only geological report on the Kashmir sapphire, the mines being located at Soomjam (Sumsam) Padar district, between 14 250 and 14 950 feet above sea level.
A later though much less detailed record, published in 1934 by the Government of India, is A Sketch of the Geography and Geology of the Himalaya Mountains and Tibet, part IV, Here is an extract: “some fifty years ago the beautiful azure blue sapphire of Sumjam inPadar, Zanskar, Kishtwar tahsil, was accidentally discovered at an altitude of 15 000 feet among rocks which have since been determined as feldspathic pegmatite veins in actinolite-tremolite lenticles in the vmarble bands of the area. The actinolite-tremolite schist appears to have been a modification of the marble. Large quantities of excellent stones were found and they yielded considerable revenue to the Kashmir government.Subsequently the actual source of the rock appeared to be exhausted though the placer deposit continued to yield a diminishing output. Later on, new veins of corundum, sapphire and pink corundum (ruby) were discovered in the area and its neighbourhood in colour, the sapphire is of a pale china-blue tint but more generally it is a rich sky blue which in the best stones becomes extremely vivid. Occasionally a more slaty blue tint appears. The colour is irregularly and unevenly distributed in the sapphire crystals, being found in stripes and patches of different dimensions among the milky grey and colourless corundum. A reddish tint is also found, though somewhat rare. Where found it varies from pale pink to rosy red and in a few cases to carmine with a slight blue tone in the red.” Gübelin and Koivula describe and illustrate some of the characteristic inclusions of Kashmir sapphire in Photoatlas of Inclusions in Gemstones, second edition, 1992. They describe a ‘milky turbulence’ (some have called this effect ‘sleepiness’); this is thought to be caused by a profusion of cavities and exsolutions which diffuse the incident light. Mineral inclusions are rare but the authors illustrate a fine crystal of tourmaline magnified by 32. Since blue sapphires from other places usually show a rather more defined inclusion pattern anyone testing a sapphire with no obvious inclusions should not rule out a possible Kashmir specimen.