Cosmic Shimmer Ultra Thick embossing crystals are semi-opaque. They can be used over a clear ink as well as colored. The color of the ink used underneath the embossing crystals will subtly affect the overall effect. When they catch the light, the iridescent shimmering color can be seen. The crystals are larger than those in a standard embossing powder so if used with a stamp and ink pad, it is recommended that they are heat set from underneath. Alternatively, use in a Melt Pot and pour over a rubber stamp or into a mould.