Natural precious opal from the Welo area of Ethiopia, with flashes of green, orange and red, and some matrix. Most people think of flashy precious opal from Australia, but opal actually occurs in various colours and around the world. The Ethiopian opal is a relatively new discovery and can have the "play of colour" that defines precious rather than common opal. Like all precious opal the lighting makes a difference to how it shows, and I have tried to photograph this to best advantage. This specimen is discreetly glued to a black plastic base for display.
The final photo shows examples of all the different colours and forms of opal that I have on my web site (at least until some sell). Just put "opal" into the search box to see them all.
5/8 inch (1.6 cm) wide, 5/8 inch (1.6 cm) deep and 7/16 inch (1.1 cm) tall.