gems

I was wondering about a good way to do gems like you do with airbrush in ink, but with a different colours. Do you have a suggestions for doing a nice bright purple, bright blue or teal coloured gems? And what brans of ink work best? Freak flex? Badger minitair? P3? Tayima?

http://pinsofwar.com/how-to-paint-gemstones-on-blood-angels-terminators/

Not really what you describe but maybe it helps?

I tried the airbrushing way to do the gems the way buypainted does them on the elves. except I did base grey, just a tad of black on the upper corner and some white on the bottom. then I painted on different colours with the badger minitaire and freak flex tints. the gems look absolutely amazing. for the really small gems I just did the grey, black white by hand as it is hard to be the accurate by airbrush.