Enchanted Gemstone

The enchanted gemstone was an artifact of the Kelani Magi. It is said to hold the power to make constructs out of pure energy. When the Kelani fell to ruin, the Razormane Quilboars were quick to scavenge and covet these beautiful and powerful objects.

Source
Cairne Bloodhoof can find this in The Oracle, chapter 7 of the Warcraft III orc campaign, The Invasion of Kalimdor.