How to use Stones ?

How to use these.. Are they just a waste? please guide me 'bout them.

Those stones....are used in upgrading ......magic stones for amulets and rings ......red stones..yellow ..blue ..green ...stones are used to upgrade weapons

I forgot wind stone and dark stones for weapons also......and iron stone for your armor

Basically you have to use gold to max out your weapon and depending on the element you use five stones to break the limit