SOLID GOLD

If copper and silver are used, the gold will retain its natural color. At the same time, the greater the number of karats, the more yellow the gold W11 be. For example, 22-karat gold will be yellower than 18-karat gold, and 18-karat gold will be yellower than 14-karat gold. If only silver is used (and sometimes small amounts of copper and zinc), the result is green gold.

If only copper is used, the color will be pink or red. If copper, zinc, and nickel are used, the gold will be white. The use of other metals will create other colors. In all cases, the type of metal doesn't change the karat content-what counts is the proportion of gold used.

Although we take such colors for granted, someone had to invent them-and the invention wasn't always easy or successful. In the seventeenth and eighteenth centuries, for instance, alchemists, goldsmiths, and even apothecaries were trying to find a way to turn gold white.

A German apothecary's assistant named Boettger was rumored to have succeeded at the beginning of the eighteenth century. At that time, many royal courts had their own goldsmiths, men who might become wealthy but who were also virtual prisoners, so valued was their artistry.

When Frederick I of Prussia became interested in Boettger's work, the goldsmith fled. He was found by Augustus the Strong, ruler of Saxony and king of Poland, who decided to keep Boettger at his court, despite the reward offered by Frederick -and the threat of war to get him back.

Augustus was successful in keeping the poor apothecary's assistant locked up for fifteen years, but Boettger never gave away the secret, if he ever had it. Finally, though, he did reveal the secret he did have, that of making porcelain, what has been called "whitegold," and became the director of the famous Meissen porcelain factory in Dresden.