Gemstones: Prices, Sources and Mines

Gem value comes down to rarity, colour and where a stone was mined, and the articles here work through all three. Price guides cover painite, musgravite, jade, tanzanite, padparadscha sapphire and several kinds of opal, while other pieces trace particular sources such as Zambian and Sandawana emeralds, Oregon sunstone, Afghan lapis lazuli and the Merelani Hills tanzanite deposits.

The collection also follows what happens when a famous mine shuts, from Sleeping Beauty turquoise to Argyle, and whether tanzanite supply is running out. Collectors and hobbyists can read about public gem mines in Texas, digging for opals in Australia and minerals found in Arkansas, and anyone weighing a purchase can check what to look for in a sapphire, opal or gemstone mine for sale.