The socket choices are: Diamond provides a five pound encumbrance reduction for one hour. Ruby produces a jet of steam which removes a frostbite effect. Sapphire casts the forage spell. Pearl casts water walking.
Each socket has a twenty-four hour cooldown, so having a second socket of the same type provides a second use with its own twenty-four hour cooldown.
Diamond encum reductions stack duration, NOT encum reduction. >