Yeah - thankfully there are no biome-dependent ores in GregTech, altho my experience so far with NOT finding a Grossular vein (I've been exploring at elevation 25 entirely under the ocean areas) makes me wonder about that... lol
Do you know the seed? If so, and you don't think it's cheaty, you could try something like Amidst to find a desert. Or this biome finder http://chunkbase.com/apps/biome-finder.