Ive never seen this drop from a gem, was rather happy to get them, both are for ranger, ruby is for top and goblet for greaves. Personally I think deciples should drop these items rather than a stupid peridot.
RubyDemon Stone Diamond Souls, Diamond Crystals IMO should all drop from Meteoric-Gem Bosses, makes sense to me I guess.
I hope you were saying they need to drop more. I would give my left arm for a silver goblet. A couple days ago I soloed a rednane gem______, I got a rose quartz, amethyst, and a pearl. I think the gem mobs should drop ruby as the lowest drop and a random quest item like goblets and horns. Just my thinking.