These rocks are made from one of our brightest glow in the dark powders. They are about a quarter inch in size and look similar to aquarium pellets. Since the glow pigment is encapsulated in the rocks, they are not sensitive to water like our standard glow paints. They look great in gardens, ponds, and especially aquariums.
The ultra green is the second brightest photoluminescent paint currently sold, to the best of our knowledge. It glows yellowish green for 10 or more hours, while appearing almost clear in daylight.
Photoluminescent materials absorb light energy as electrons in their atoms are boosted to high energy levels by absorbing individual light quanta, or photons. Instead of dropping back to where they originally came from, though, these excited electrons transfer to a nearby, intermediate energy level and keep much of the photon energy. Dropping back from this intermediate state, called a metastable state, to ground level is slow going. As these metastable electrons gradually drop back to ground level, they release the rest of their energy as the visible glow we see.