Crimson in the 2nd section of Onyx City and similar NPCs will allow you to refine your equipment and improve its existing bonuses.
Most ores offer a random bonus that will be applied to an equip's existing STR, MGC, RES, VIT, DEX or SPD attributes. This means that if an equip has only one positive attribute, the result won't be random at all and that attribute will be the one improved.
Range determines how much an equip must be upgraded to use a smithing option. For example, if an equip has no upgrades, the range starts at 0 for the option you need. If an equip has +7 upgrades already, you must choose an option that has a range it falls into, such as +5 to +10.
Some rare ores offer a very specific bonus. For example, Inferno Ore made by the Limited Edition Soul Puppet Frau Stein will always increase an equip's .
Refining equipment has a fail chance that can be reduced by the Player Growth Attrbute Smith and associated Credit Shop Key Items.
Equips that have failed refining will remain unaltered.