Ebony Ore (Skyrim)

Can be mined at:

Red Belly Mine, north of Riften - 3 veins found at the bottom of the mine. (also 3 Ores can be found by the smelter in Shors Stone)

Throat of the World, highest point in the game - 2 or 3 veins on the very top.

Gloombound Mine, south-west of Windhelm - Has alot of veins in the mine, maybe 5-10.