Shardleaf Gel

Shardleaf gel naturally contains a mixture of phosphorescent compounds and traces of various radioactive materials endemic to their native ranges, giving the material a faint glow even without further processing. The concentration of both of these constituents can be achieved by distillation, a process which must be carried out under sealed hoods to prevent the manufacturers from being poisoned. The resulting paste can blended with a binder and applied directly to a surface (i.e. the needle on a gauge) as a paint, but the more common option is to inject small quantities of the substance into sealed capillary tubes which are shaped for the desired application in the manner of tiny neon lights. Additional phosphorescent coatings can enhance the lighting effect. In either case, a thick layer of glass is placed between the now-glowing object and the user to absorb the remaining radiation (mostly alpha and beta particles) and to prevent tampering which might cause the hazardous gel to become dispersed into the environment.

Shardleaf gel indicators typically keep glowing on their own until a sufficient number of half-lives have passed that it no longer emits enough radiation to induce phosphorescence. Over time, the light provided fades as more and more of the elements (typically tritium and certain metals) undergo decay. A properly manufactured shardleaf gel lighting surface will remain legible at night for around 20 years, after which the phosphorescent chemicals will still be able to be energized by external sources (i.e. the ultraviolet light of the Distal Tesseract) for an indeterminate amount of time.