Gold: Their shapes look like hieroglyphs on ancient tab lets. It is said that the two are somehow related.Silver: Its flat, thin body is always stuck on walls. Its shape appears to have some mean ing.Crystal: Because different types of UNOWN exist, it is said that they must have a variety of abilities.
Prof. Lotus' Notes: In the original Silver and Gold games, because of limitations to the hardware, Unown letters were generated by using the IV values. Because of this calculation, only the letters I and V could be shiny.