Naturally pink common opal from Peru. Most people think of flashy precious opal from Australia, but opal actually occurs in various colours and around the world. The non-flashy type is often referred to as common opal. This specimen is discreetly glued to a polished black onyx base.
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.
1/2 inch (1.3 cm) wide, 3/8 inch (0.95 cm)) deep and 3/8 inch (0.95 cm) tall.