Crystal Magic

Crystal Magic is a kind of an oddity, since it spread around the Imperium quite a few years after its own subschool did, forcing quite a bit of reshuffling at Imperial Magic Guild. Even today it still isn't too popular, at least on surface of Karadia, instead being a weapon of choice for the Crystallings. Most of the potential trainers come from their lands.
It works by shortterm creation and manipulation of few types of crystals, very similar to the parasitic crystal that create crystallings. Most of the spells are identical to Metal Magic, differing only in materials they used, with crystal achieving lesser armor penetration and defensive power, instead having a wide array of special effects, linked to their colors (for example green is toxic, red very hot and so on) increasing this magic versatility.

Subschools of Crystal Magic

Glass Magic [BM] - Glass Magic originates from magical anomaly called Glass Forest. All of the glass used by it is heavily unnatural by standards of Light, being much more resistant and having a few special effects. There are no spells that utilize the parasitical powers of certain types of glass. Many believe them to be on a list of spells for knowledge of which Imperium kills.
Glass hexes are rarely encountered in the Imperium, with little knowledge about details of this subschool among feneral population of magicians. With all details known probably only by the Silver Council, a Imperial Magic Guild surpreme - and extremely elusive) leadership.
Beside Crystal Magic, it is also well attuned with general Black Magic, and also with Profane Magic.