“Tiffany stone” is a trade name used for a purple, blue and white gem material that can be cut and polished into beautiful beads, cabochons and tumbled stones. Geologically, Tiffany stone is a rock composed primarily of fluorite with smaller amounts of opal, calcite, dolomite, quartz, chalcedony, bertrandite and other materials. Other names used for Tiffany stone are “opalized fluorite,” “ice cream stone,” and “bertrandite.”

A Tiffany Stone nodule, sliced in half and polished. Can you see why some people call it “ice cream stone”?