Meteoric iron

The people know these fragments as shooting stars.

And from time to time, such Aetherial fragments are found on Nirn." The most common varieties are known as meteoric iron.

This metal is prized by armorers and enchanters for its properties in the forging of enchanted weapons and armors.

This meteoric iron is also the primary component in alien wells.

Think about all the alien wells that you come across in Oblivion.

In Oblivion

It says, surely you have seen a shooting star.

This occurs when a piece of Aetherius, spirit plane and source of magic, becomes dislodged and falls to Nirn.

Returning to the sledge for the saw knife, he began excavating the snow, and at last, after digging a pit some three feet deep and five feet in diameter, just at 5.30 Sunday morning, May 27, 1894, the brown mass, rudely awakened from its winter sleep, found for the first time in its cycles of existence the eyes of a white man gazing upon it.

This was the Woman, a mass of meteoric iron weighing, as was subsequently proved, three tons.

Originally, it was said to have been twice that size, the removal of the head having considerably reduced it, while in addition there had been generations of Eskimo chipping it for knives and spear tips.

The amount of iron which had been broken from it in this way was shown in the pile of stones lying around it.