Colbalt Ore is the lower level of the ores available in Northrend. The two best farming spots are in Howling Fjord and Zul’Drak.
Colbalt Bars are used for a large number of blacksmithing transmog items including the Cobalt transmog set and needed as a mat for some of the Saronite pieces.
When farming, you also have the chance to mine the following: