Minecraft wiki entry for Nether_Gold_Ore, associated text: Nether gold ore generates in the Nether in the form of blobs. Nether gold ore attempts to replace netherrack 10 times per chunk in blobs of size 0–16, from levels 10 to 117, in all Nether biomes except basalt deltas. In basalt deltas, Nether gold ore attempts to generate 20 times per chunk as there are fewer valid generation areas.