Afghan emerald of the Panjshir

Emerald has been mined in this valley for thousands of years and almost none of it was written down. That absence is the starting point of a 2022 study by Jessica DeWitt, Pete Chirico, Kelsey O'Pry and Sarah Bergstresser, who set out to map small-scale mining in terrain nobody could survey on foot.

Their method is the interesting part. They took geologic units already known to host emerald and re-analysed them with Landsat multispectral imagery to work out where mining was likely to be. Then they read very fine resolution satellite imagery to see what was actually happening on the ground, and ran three-dimensional topographic change detection over the mine sites to measure how much rock had moved. Combining that volume with archival grade data let them estimate production for an industry that keeps no accounts.

What they found is a working method changing under pressure. Mining is becoming more concentrated, and it is shifting away from traditional tunnelling toward mechanised surface excavation. That has consequences the paper takes seriously: the authors go on to consider how recovery might be improved, because moving more rock faster is not the same as getting more emerald out of it, and a stone shattered by a careless blast is worth nothing.

The valley itself is 150 kilometres north of Kabul, near the Hindu Kush, split by the Panjshir River, and the name means Valley of the Five Lions. More than a hundred thousand people live there, and it holds Afghanistan's largest concentration of ethnic Tajiks. It became its own province in April 2004, having been part of Parwan.

This is not a place to plan a trip around. It is a place whose stones you will meet in a dealer's case, and now you know roughly what it cost to get them out.