Northstar's Illuminati boro glass contains URANIUM so it will fluoresce under UV light. We have found that short wave UV light in 365nm-405nm works best. We feel this color has amazing working properties and can be used in any type of flame. This glass can be used in any application with no problems of cracking or incompatibility. The color in natural light is an amazing transparent neon green with many opportunities for layering. If you are cold working use standard safety practices regarding personal protection.