BEACHES: NOT JUST SUN AND SURF

For many of us, the word "beach" evokes pleasant images of summers spent enjoying sun, sand and surf. But for geologists this word has a more specific meaning, referring to waterborne accumulations of sand that sometimes host economic concentrations of gemstones and other valuable minerals.

- Steve Voynick

The world's beaches have yielded tons of gold, millions of carats of diamonds, numerous fine specimens of nephrite jade, huge amounts of amber and much of the world's titanium. Some beaches, however, are not known for their valuable metals and minerals, but for their unusual colors-white, black, green and even purple.

NOME'S BEACH OF GOLD

While beaches today draw hordes of summer vacationers, in 1900 the Bering Sea beaches at Nome, Alaska, attracted more than 20,000 adventurers and miners in a wild search for placer gold.

Nome's gold occurred along a narrow, 30-mile-long tidal beach where the traditional mining-claim system was largely ignored. The beaches were wide open to everyone and miners initially worked with gold pans, then sluices and rockers, later with pumps and hoses, and finally with dredges. Nome's location, just 125 miles south of the Arctic Circle, limited mining to the brief summer season.

Dredge miners still recover gold at Nome today. Over its 123-year history, the Nome Mining District has produced 3.6 million troy ounces (111 metric tons) of gold, most of it from the beaches. The Nome gold rush is memorialized in the song North to Alaska and the 1960 John Wayne movie of the same name.

NAMIBIA'S DIAMOND BEACHES

Beachcombers sometimes whimsically imagine the water-polished bits of colorless quartz glittering in the shoreline gravels at their feet to be diamonds. But imagination is not necessary on the beaches of the southwest African nation of Namibia, where the sands are yielding millions of carats of diamonds.