image by IBE Opals Opal, the national gemstone of Australia, which produces 97% of the opal in the world. Opals can be almost any colour, from white to black, from green to red, blue to pink etc. Of these, red and black are the rarest (black is depicted above). The refraction of light in the opals internal structure causes these different colour, and this effect can be enhanced by placing a layer of opal onto a dark stone.

image by IBE Opals

Opal, the national gemstone of Australia, which produces 97% of the opal in the world. Opals can be almost any colour, from white to black, from green to red, blue to pink etc. Of these, red and black are the rarest (black is depicted above).

The refraction of light in the opals internal structure causes these different colour, and this effect can be enhanced by placing a layer of opal onto a dark stone.