rockysalamander|1472344650|4070729 said:It looks like a manufactured photoluminescent stone. They are made in a few way.
1) Quartz that is porous enough that the phosphate used to treat it remains beyond the surface.
2) They are made as a fully manufactured stone and range in size from gravel on up to small boulders.
3) It could be glass coated in a substance that is just a thin coating
4) about 1 million other creative ways
If it was natural, some minerals can glow for a very short time if exposed to intense UV light -- calcite, celestite, colemanite, fluorite, sphalerite, and willemite (maybe others). It does not have a crystalline + color that looks like any of these natural minerals.