Dutch metal

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

• noun An alloy of 80 percent copper and 20 percent zinc used to make low-priced jewelry and in thin sheets as an inexpensive imitation of gold leaf.

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

• noun a form of brass, being an alloy of about 80% copper and 20% zinc, produced in thin sheets and used to make cheap jewelry