Some of the items that you may disenchant can be quite expensive but this is part of the process regrettably. Then the WOW Enchanting Guide to break them down into its core to reuse for enchants. Just check you are disenchanting the correct items as it cannot be undone.  Formulae can be located from monster drops or hidden trainers. Different types of dusts is what you will acquire if you disenchant armor. Weapons you find – mainly essence, maybe some dust and rarely, a shard. You will get a shard if you disenchant blue items. Purple Items you find – Nexus Crystal, Void Crystal.