Gold is one the world's most precious metals. It is, indeed, treasured in every culture for its beauty, yet it is so much more than a glittering metal. Gold is soft and ductile that one ounce can be rolled into a fine wire five miles long, so malleable that it can be hammered into sheets so thin that thousands and thousands piled atop one another would measure less than an inch in height! Gold is present almost everywhere around us - in seas and rivers, in earth's crust, and in plants -- but it is very difficult and expensive to extract.

Because pure gold is so very soft, it is usually mixed with other metals. When two or more metals are mixed together, we call the resulting product an alloy. Many countries have established minimum standards that must be met for items to be legally called "gold."

For example:
USA - It must be at least 10K(10/24, about 41.6 percent) to be called "gold".
England and Canada - It must be at least 9K (9/24, about 37.5 percent).
Italy and France - It must be at least 18K (18/24, about 75 percent).

Pure gold is always yellow.