From this thread:
The crystal focus only works on plain no-ego weapons.
Further, from this thread:
Ah yes... the Crystal Focus. When melded with a normal, plain weapon,
the results are great. More damage, random magic damage, pushed crits,
pushed APR, pushed spellpower. An all-terrain bonus-fest.
Sadly bugged to hell.
Occasionally (had it go both ways) on the Imbue screen it will not
activate, and the natural reaction of the erstwhile Player is to click
multiple times apon the weapon out of sheer indignant righteousness.
This has the unique effect of actually imbuing the crystal focus each
click making a game-breaking kill everything weapon with a typical
damage range in the hundreds of thousands. Read the new sig of Darkgod
for the record damage of this bug. (I think its' around two Billion
damage - the RNG flags the sucker with an exponential value!)
Awesome, right? It also makes your Rod of Recall dissappear, rendering
this bug a potential game-breaker.