King Opal

About Opal

Our Opals

Opal Formation

Opal is primarily composed of a solution of silicon dioxide and water. As water runs down through the earth, it picks up silica from sandstone, and carries this silica-rich solution into cracks and voids, caused by natural faults or decomposing fossils. Once the water evaporates, it leaves behind a silica deposit. This cycle repeats over very long periods of time, and eventually opal is formed.

Opal is formed from tiny silica spheres, contained in silica-rich solutions in the earth form and settle under gravity in a void to form layers of silica spheres. The solution is believed to have a rate of deposition of approximately one centimetre thickness in five million years at a depth of forty metres. When the spheres are the same size and are arranged in a three-dimensional grid, negatively charged areas are created in the gaps between the spheres. If those negatively charged areas are as big as a wavelength of visible light, then colors will be visible. For precious opal the sphere size ranges from approximately 150 to 400 nanometres producing a play of colour by diffraction in the visible light range of 400 to 700 nanometres.

JAA Member

JAA Member

Established in 1931, the Jewellers Association of Australia (JAA) works to represent and protect the interests of the jewellery industry and its consumers. With a membership of around 1200 outlets, the JAA is a national organisation that covers all areas of the jewellery industry - from manufacturing, wholesaler, distribution, to retail.

Opal Association Member

International Colored Gemstone Association Member

The ICA is a worldwide body specifically created to benefit the global colored gemstone industry by advancing and promoting the knowledge and appreciation of colored gemstones.