Minecraft wiki entry for Redstone_Ore, associated text: In Java Edition, redstone ore generates in two batches per chunk. The first batch attempts to generate 4 times per chunk, in blobs of 0–10, evenly from levels -63 to 15. The second batch attempts to generate 8 times per chunk, in blobs of 0–10, from levels -63 to -34, being more common the lower the elevation. Redstone ore can replace stone, granite, diorite, andesite, tuff, and deepslate. If it replaces tuff or deepslate, it will become deepslate redstone ore.