precious metal

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of several metals, including gold and platinum, that have high economic value.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A rare metallic chemical element of high economic value, such as gold and platinum.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of the less common and valuable metals often used to make coins or jewelry