Randy Schoonover, age 13, of Canby, Ore., for his question:

WHAT IS THE DIFFERENCE BETWEEN WHITE AND YELLOW GOLD?

Gold is a metal found in small amounts throughout the world, and it is precious and highly prized. In its natural color it is bright yellow. Since it is very soft, it is usually mixed with harder metals such as copper or silver. Pure gold is called 24 carat gold; the number of carats describes how many parts in 24 are gold.

White gold is an alloy of gold made with platinum, palladium, nickel or nickel and zinc. There's also a green gold where the alloy is silver. Copper gives a reddish yellow color to the gold. The jewelry industry uses all types of gold alloys.