Siderite

Siderite is a valuable material used in the fortification of equipment. When other equipment is not available for melting down to fortify another piece of gear, siderite can be used in certain quantities to instantly increase the fortification of the gear by 1 level.

Siderite Bags
Siderite will be stored in your own private stash of Siderite for use. In some cases you may acquire bags of Siderite out in the world as reward, or combine shards stolen through Pickpocketing in order to form a full bag of the material. Simply click on the item in your inventory to acquire the Siderite within.

Fortifying with Siderite
When there is no other gear available to Fortify, clicking the “Add Automatically” button will add the required amount of Siderite to the Fortification Menu in order to up the Fortification Level by 1 level. The higher the level, the more Siderite will be required to do this.