Ganesh Himal crystal

The Ganesh Himal runs along the Nepal-Tibet border northwest of Kathmandu, and the quartz that comes off it is some of the most transparent in the world. The productive ground is in Dhading District in Bagmati Pradesh, and what makes the crystals what they are is written into how the mountains were built.

This is the Greater Himalayan crystalline complex, high-grade metamorphic rock, schist and gneiss, thrown up by India driving into Asia. Collision opens tension fractures. Hot mineral-rich fluids move through those fractures and grow crystals slowly into the open space, which is the alpine-fissure recipe that produced the classic quartz of the Swiss Alps and produces it here on a larger and younger mountain range. Slow growth in an undisturbed cavity is what buys the clarity.

The signature look is water-clear quartz with chlorite in it. Usually the chlorite is spread through the body of the crystal in green clouds and phantoms; occasionally, and this is what collectors chase, it sits only at the termination. Groups often come with white albite for contrast. The material that defined the locality in Western collections started arriving around 1999 and through the 2000s.

The mining is the part outsiders underestimate. Access is days on foot or by rough vehicle through remote mountains, work is seasonal around monsoon and snow and depends on local agreement, and every specimen that reaches a show was carried down a Himalayan slope on somebody's back.

Two honest notes. This is serious high country and the diggings are not a destination without local arrangement and proper acclimatisation. And the whole chain runs through Nepali diggers, porters and Kathmandu dealers, so buying in Kathmandu is both cheaper and fairer than buying it at the far end. Thamel is where it surfaces, and a good dealer will tell you which valley a piece came out of.