Truesilver

Truesilver is a metal that can be mined at level 205, although it can't be smelted until 230. Truesilver Deposits can also produce gems. Gems found in Truesilver Deposits include Aquamarine, Citrine, and Star Ruby. Truesilver Ore can be smelted into Truesilver Bars by miners.

Interestingly, Truesilver has been noted to be a material that is both incredibly light and stronger than steel.

Warcraft RPG
The magical and mysterious truesilver is greatly sought for its arcane properties, especially for its use in armor treatments. By the rigorous application of dweomers, armorers boast that this armor treatment "can give mortals a taste of godhood". While armorers are not immune to hyperbole, there’s little doubt this treatment produces extraordinary transformations. Only heavy armor may receive the truesilver treatment.

Gems mined

 * Citrine
 * Aquamarine
 * Star Ruby