Coltaho

Tested this out today.

For spells we got around a 25 second internal cd, with a very high 50%+ proc rate as others have said.

For melee:

Mage: 117 procs of 1001 hits (11.69%) using a 1.8 speed. (26% proc crit rate)
Elem Shaman: 80 procs of 500 hits (16%) using 2.7 speed (27% proc crit rate)

The melee and spell procs are not linked, as instant cast spells between melee swings proc'd back to back with the melee proc.

Edit add: Also can proc off things like windfury.

It does not stack with tongues or tclap.

It is not effected by mage talent Ice Shards, but % dmg modifiers such as soul link and CSD metagem effect it. Spell/frost damage increasing debuffs effect it, but wasn't able to test all such as Winter's Chill.

W/O Mage T6 helm (CSD): 155 hits, 232 crits
With: 155 hits, 239 crits

The only talent I have that would effect this is Playing With Fire (3% increased spell damage: 150*1.03=154.5 round up to 155)

The procs seemed to be really stringy, sometimes lots in a row, other times very very few for a long while. Probably just like all other procs in that sense.