Fundraiser for Australian wildlife. Fire opal from Mexico. The varied and bright colours are natural. The centre specimen is mounted on a mirror, which reflects light back through the opal.
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.
Left: 5/8 inch (1.6 cm) wide, 3/8 inch (0.95 cm) deep, 7/16 inch (1.1 cm) tall. $12
Centre: 1/2 inch (1.3 cm) diameter, 1/4 inch (0.6 cm) tall. $12
Right: 5/8 inch (1.6 cm) wide, 5/16 inch (0.8 cm) deep, 3/8 inch (0.95 cm) tall. $12