Titanguard Wristplates

Fantastic set of bracers considering that mastery is the best stat in game for "most" tankingspecs to date have mastery as most valuable stat.

if one would buy the regs from ah today the item will cost
(wowhead.com prices)

Volatile Fire Bar 14 g 76s 97c * 20 = 2953g 94s
Hardened Elementium Bar           141g 97s     * 8  = 1135g 76s
                               = 4089g 

So the regs to that point is cheap considering the item! But if you played in WotLK you might remember the Primordial Saronite who was worth some thing several thounsands of gold even months after patch release. Making an guess on the cost for the Essence of Destruction is imposible, but expect huge amounts.