Zircon Sources

Australia

Over an estimated third of the zircons mined annually (gem-quality and non-gem quality combined) come from Australia. Much of the gem-quality material comes from three locations with alluvial deposits of alkaline basalt: New South Wales, Queensland, and Tasmania. Located in the Northern Territory, the Mud Tank Zircon Field gets its name from its deposits of typically brownish zircons. All these Australian zircon sources yield gems with earthy hues, such as brown, red, and yellow.

Some Australian zircons may also show a “cat’s eye” effect. Known as chatoyancy, this optical phenomenon results from long parallel inclusions. When a lapidary cuts one of these included zircons into a cabochon, you can see a distinctive “cat’s eye” on the gem’s curved surface.

Australia has also famously produced the oldest zircon crystals on Earth. At 4.404 billion years old, these are the oldest known minerals on Earth. However, these ancient specimens are tiny

…

---