Minecraft wiki entry for Diamonds, associated text: Even after all this building and grinding, it's by no means guaranteed to get the desired enchantment. If Silk Touch is obtained instead, that can be used to collect diamond ore instead of gems. When a few diamonds (say, for a diamond sword) are required, the player can always place that many blocks and use another pickaxe to mine them, but save the rest of the ore for when a Fortune pickaxe is available.