Do all rubies have florescence under black light?

Question

Do all rubies have florescence under black light?

Answer 1

Rubies will fluoresce red if they have no iron impurities.

Fluorescent rocks include fluorite, calcite, gypsum, ruby, talc, opal, agate, quartz, and amber. Minerals and gemstones are most commonly made fluorescent or phosphorescent due to the presence of impurities. The Hope Diamond, which is blue, phosphoresces red for several seconds after exposure to shortwave ultraviolet light.