Gold was one of Middle-earth's precious metals. Ever since the great god Eru created Arda, it had existed within the earth as a nonrenewable resource.
This gleaming golden metal had not always enjoyed such an exalted status. Back in the First Age, the Dwarves preferred copper or iron to gold and silver. Only at some later point did they accord gold a higher standing.
Elves and humans, meanwhile, preferred silver, especially the Noldor among the Elves and the Númenóreans among humans.
Out of reverence for the stars, the Noldor Elves of the First Age liked to plate their armor with silver. In the sunlight, every warrior clad in silver-plated armor shone like a brilliant star, dazzling to behold.
The Númenóreans preferred ornaments wrought from silver. The crowns of Gondor's kings were generally made of silver, while the kings of Arnor wore silver or mithril circlets set with gems.
This tradition might have come from their ancestor Eärendil. The Half-elf who had personally slain Ancalagon had a certain fondness for silver, as seen in the white chainmail recorded in poetry, or the great white ship Vingilótë, the "Foamflower."
Only in the Second Age did the Noldor Elves develop a definite preference for gold, particularly the Elven craftsmen of Eregion. Beyond fashioning gold into ornaments, they also inlaid their buildings with the shining metal, making their homeland look all the more splendid and dazzling.
The Dwarves of Durin's Folk shared this habit. It was said that in Khazad-dûm-Moria under Dwarven rule-their boundless wealth from mithril allowed them to roof their halls with gold and pave their floors with silver. Records of that splendor still survived in certain people's books.
But the Half-orcs had already plundered nearly everything there. Most of that wealth was probably now piled within the tower of Barad-dûr under