Aulë is a Lord of the Valar, one of the Aratar, and the third Lord of the Valar in order from Manwë and Ulmo, so he is great indeed.
Singer of the Earth, Aulë created all land including the gems and metals. His craftsmanship is of the finest, and he is incorruptible by mere "things" because he loves the making, but is not possessed by the item. Thus has he earned the jealousy of Melkor. Aulë is the originator of the Dwarves, a work blessed by Eru with the Flame Imperishable so that they came to life. Aulë's wife is Yavanna.
Aulë is known as Mahal to the Dwarves, who believe that he cares for them and has a hall set apart for them in Mandos where they go to him after death. They say he told their seven forefathers that Eru will hallow them so that they will be placed among the Children of Eru in the End. Then they shall serve Aulë, aiding him in rebuilding Arda after the Last Battle, and the seven forefathers shall return under their own names to live with their kin. (Silmarillion)
Also he is called by the names of Taglos and Martamo.