Like all of our rainbow opals, these 4mm spheres have a clear transparent base and flash the colors of the rainbow with brilliant red, yellow, blue, and green fire. Because of its transparency, the outline of the stone disappears in clear boro (which is why some people call them "ghost opals") and flashes only the rainbow of opal fire in the middle of the glass. Rainbow opals create a cool effect when you want to put the fire in the glass with less emphasis on the shape of the opal.
Did you know our Gilson Created Opal does not decompose, off gas or release any substances when heated to very high temperatures? Read more about our testing here