The harvesting of SongCrystal is roughly the same as mining for any other mineral or ore.  Of course, the subterranean races, especially Dwarves and Gnomes, excel at finding the substance.

However, to work the SongCrystal into usable shapes requires a blend of magic and music which seems to be found most frequently among Elves.  Dwarves, Humans, and Gnomes can mine and cut the stones but typically cannot create the more subtle effects which Elven 'Crystal workers are capable of.

SongCrystal can come in any color imaginable, though the color typically represents the 'school' of magic the stone is most closely aligned with.  The 'standard' colors are as follows:
 

Schools of Magic and SongCrystal Colors

School	Color
Abjuration	Green
Alteration	Blue
Conjuration/Summoning	Orange
Enchantment/Charm	Yellow
Greater Divination	Purple
Illusion	White
Invocation/Evocation	Red
Necromancy	Black