Gemstone which ranges in colour through yellow, red and orange to green.
Colourless, golden-brown and sky-blue versions are produced by heat treatment.
Most of the mineral suitable for gemstones comes from the Far East and Sri Lanka. Yellow and brown shades of zircon were often termed hyacinth, and transparent or colourless types are sometimes known as jargons or jargoons.
Colourless zircons are sometimes used as substitutes for diamonds, but are not as hard or brilliant.
Zircon occurs in many different colors, including red, pink, brown, yellow, hazel, black, or colorless. The color of zircons sometimes can be changed by heat treatment. Depending on the amount of heat applied, colorless, blue, and golden-yellow zircons can be made. In geological settings, the development of pink, red, and purple zircon occurs after hundreds of millions of years provided the crystal has sufficient trace elements to produce color centers. Color in this red or pink series is annealed in geological conditions above the temperature about 350 °C.