There are two types of colour available: base and "elemental".
Available base colours are as follows: blue, green, cyan,
red, magenta, brown, lightgrey, darkgrey, lightblue, lightgreen,
lightcyan, lightred, lightmagenta, yellow and white.
Elemental colours are: fire, ice, earth, electricity, air, poison,
water, magic, mutagenic, warp, enchant, heal, holy, dark, death,
necro, unholy, vehumet, beogh, crystal, blood, smoke, slime, jewel,
elven, dwarven, orcish, gila, mist, shimmer_blue, decay, silver,
gold, iron, bone, random. See view.h for comments on each.