Augmentations
Augmentations are new type of item introduced with the LDON expansion. Augmentations can be added to certain items in order to improve that item in some way. Augmentation Gems can only be found (currently) in Lost Dungeons of Norrath adventure zones. Better augmentations will obviously drop in more difficult adventures.
There are 8 types of augmentations, these are determined by their 'Type', and you will notice most items in the game now have a type on them to indicate what types of Augmentation Gems will fit into them. Some augmentations will fit into all types.
Type 1 - Single stat enhancements
Type 2 - Multiple stat enhancements
Type 3 - Worn effects
Type 4 - Weapon Procs
Type 5 - Single Weapon Damage additions
Type 6 - Multiple Weapon Damage additions
Type 8 - Plane of Time Items Only
Note that augmentations can change your items slot permanently! If you have a item which can be worn in the Ranged Slot or as a Dagger and you equip a ranged slot only augmentation you will no longer be able to use the item as a weapon! So be careful using your augmentations.
Using Augmentations

To use an augmentation go to a camp and look for the bird bath resembling container known as an Augmentation Sealer. You can find one in each camp. By left clicking on the Sealer your inventory will open as will a two-slot combining box. Simply drop the item and the augmentation you wish to add to it in the box and hit combine. You will get your upgraded item placed back into your inventory.
If you wish to remove the augmentation at some point you can do so by first determining what slot the augmentation is in on your item. Items can have a Slot 1, Slot 2 or Slot 3, or sometimes multiple slots!
To remove the augmentation simply put the augmented item and its relative solvent into the augmentation sealer and hit combine. Slot 1, 2 and 3 solvents can be purchased from the Magus NPC in camps for approx 11pp.
Note however that the augmentation gem will be destroyed and you will only be left with your original item.
Keep in mind that the slot the augmentation is in is not relevant to the type of augmentation. If you have a type 7 augment it will be in the item's Slot 1, Slot2 or Slot 3. Pick the appropriate solvent for the slot the augment is in.