Simply requesting the gems (and any other ores) from this mod get support for UBC texture support. The mod author address how to do that here: http://www.minecraftforum.net/topic/2314333-172-164-underground-biomes-constructs/page__st__340#entry32159150

@Adubbz close. An addon is a better place for this: http://minecraft.curseforge.com/mc-mods/227992-ubc-ore-registrar Native support cause many issues.

I'll see if I can do this for 2.0.2 depending on whether or not it is relatively trivial