Eloraam is doing some funky magic with overloading block IDs. The ore does not display in NEI because it does not exist as a separate item. There is only the general "gem ore" item, which is overloaded with all three gem types, the first being ruby ore. Which is why that one shows in NEI as occupying that block ID, when in fact it is only one of three.
Note that this is different from having different items told apart by damage values of the same block ID. The gem ores literally have exactly the same ID, down to exactly the same damage value. And yet they still generate properly in the world in separate deposits, do not stack with each other, drop different drops and participate in different recipes. I have never seen anything like it in other mods, and I have no idea how Eloraam did it, but gem ores aren't the only blocks she did it with.