Opal

Tap it to tilt it and roll flashes of color across it. Pick an opal in the Splash tab.

Opal is made of tiny balls of silica, the stuff of quartz and sand, with a little water between them. In precious opal the balls are packed in neat rows, and light passing through them splits into flashes of color that change as the stone moves. This is called play of color. Fire opal is named for its orange body. Opal is cut into a smooth dome called a cabochon, not into facets.

Tap it and it rocks in the light while patches of color roll across it, changing as they go. In the Splash tab, pick a white, black or fire opal. Most of the world's opal comes from Australia.

This link opens it in the Playground. To put it on your own page, add the element and one script tag. Every option.