I hope you don't have too many Sha Crystals saved up for this upcoming patch. The 5.4 PTR has new epic craftable PvP gear on it which will likely disenchant into them, and some of these pieces will take very few materials. Six Bolts of Windwool Cloth, for example, will make you a nice disenchantable purple cape. The Sha Crystal from this can be turned into two Ethereal Shards, each of which can make three Mysterious Essences.
Right now, the vast majority of enchanting materials are made through disenchanting gear crafted by tailoring or jewelcrafting. Jewelcrafters turn green quality gems into rings and amulets which DE into a lot of dust and a few essences. Tailors make blue PvP gear that disenchants into shards. Sha Crystals are only made on the daily cooldown that enchanters get, or through disenchanting epic gear obtained in other ways than crafting. Patch 5.4 will change everything. These methods will still work, but it'll get you more materials per bolt of cloth if you use the new recipes. Each purple Crystal will be able to be broken down into two blue Shards, which can be broken down into 6 green Essences. This new way will make more enchanting materials per cloth than the existing ways.