The white crystal cost about 1.5 million when it was at the vendor, before that it was a beta only drop (so I've been told).
I would love to see the crystals brought back or even given schematics. I (stupidly
) bought the Cyan Critical crystal for my Sorcerer, which I've since switched out for a black/orange power crystal (no more normal colours for me!), but I do miss my Cyan crystal <3