I am totally loving how those crystals are looking
Me too. The emerald one took no effort at all, as the texture was used as is 4x1 column texture. Looking at it this morning I can't believe I made that half-asleep last night. The other I had to combine 4 images to get that hue mix, but it was obviously worth it. I'm debating whether or not to make them partially transparent, or leave them opaque. Either way, that will require a crystalline env map.
I forgot to make the ruby seamless. This morning I put together three more textures, but also forgot to make those seamless. They include: white quartz with a blue shine, blue quartz, and magenta amethyst.
I'd like to find a suitable dark emerald, and a bright yellow that isn't simply transparent. I have a bunch of gem and mineral books, so maybe I'll just take pictures out of that and use them instead of having to hunt the internet.