Decorative Long Shaped Vaseline Bowl, L:20" W:3.5". A history of Vaseline Glass was that primarily was made before WWII and one of the primary ingredients used to make the glass was uranium. When placed under a black light (or ultraviolet rays), vaseline glass will "glow" or fluoresce. The high energy emissions of electrons from the black light cause the uranium oxide particles in the vaseline glass to become unstable thereby causing this fluorescense. No other transparent antique glass will glow thus making vaseline glass truly unique in the antique world as it can always be verified to be true vaseline by using a black light. There is no other compound added to glass which will cause this effect except URANIUM. The yellow-green glow is characteristic of uranium-bearing glass.Vaseline Glass can be yellow, yellow-green, or green. Individual collectors each have their own preference as to the exact color of vaseline glass collected. LifestyleAntiques.com is the web site where one can shop on line or if you are in the area we are an antique dealer in Summerland, California just 3 minutes south of Santa Barbara. Specializing in European Antique Furniture and our accent is antique lighting for your home, or office with handmade parchment shades adorning the selection of unique lamps. We specialize in Decorative Arts and French furniture as well as antique furniture from Spain and Italy, you will find the shop warm and inviting.