Minecraft wiki entry for Hardcore_mode, associated text: Once fully equipped, go further down and collect diamonds. Only seven are necessary, although more is better (2 for a sword, 3 for a pickaxe and 2 for an enchanting table. These and full armor total up to 31 diamonds.) Use the diamond pickaxe to mine at least 10 pieces of obsidian for a Nether portal and an enchantment table (4 are enough if the player builds the portal using a bucket).