Zircon
Earth's oldest gem — Australian zircons date 4.4 billion years. December birthstone famous for high dispersion; Cambodia's Pailin blue zircon and Ratanakiri, plus Sri Lanka and Vietnam supply the trade. Not to be confused with cubic zirconia.
Known origins & mines
Pailin Gem Fields · Cambodia
Khmer Rouge heartland turned gem city — Pailin blue zircon glows with diamond-like dispersion after gentle heat treatment; basalt gravels al…
Ratnapura Gem Fields · Sri Lanka
"City of Gems" — 2500 years of pit mining in river gravels yield ruby alongside nearly every other gem species. Sri Lankan ruby leans pink (…
Anakie Sapphire Fields · Australia
Central Queensland basalt fields (Rubyvale, Sapphire, Anakie) powered the world sapphire market for a century with deep blue-green stones, m…
Harts Range Zircon · Australia
Australian outback alluvials yield large reddish-brown zircon heated to blue and golden colors — Harts Range gemtraverse feeds Asian cutting…
Ratanakiri Zircon Beds · Cambodia
Northeast Cambrian basalts produce colorless-to-blue zircon rivaling Pailin quality at gentler prices — heat treatment near Banlung turns cl…
Tunduru Fields · Tanzania
River-flat diggings discovered 1994 producing rainbow sapphire parcels alongside spinel, garnet and rare taafeite — one of Africa's most div…