Robert Sorlie, a veteran musher from Norway, was the first to reach the halfway point in this year's Iditarod sled dog race. As a result, Sorlie will take home $3,000 worth of gold nuggets. What do you do with gold nuggets—melt them down and sell them?
No way. Natural gold nuggets are collector's items; you'll get more per ounce selling them whole. Today refined gold trades at about $445 per ounce (near a 15-year high); even the smaller gold nuggets sell for about $560 per ounce. Bigger nuggets are harder to find and can fetch more than $1,000 per ounce. If Sorlie melted down his prize nuggets, he'd probably waste half their value.
Prospectors find only a small percentage of the world's gold in the form of nuggets, or bits of placer gold. "Placer" gold deposits are those that accumulate in the sediments of stream beds. The smallest nuggets, called screen gold, weigh less than half a pennyweight, or three-quarters of a gram.
Gold is measured using troy weights (as opposed to the more familiar avoirdupois weights): 24 grains make a pennyweight, and 20 pennyweights make a 31.1-gram troy ounce. The prize nuggets at the Iditarod ranged from about 12 grains to about 3 pennyweights. Dealers say that a gold nugget of 1 troy ounce is about as rare as a 5-carat diamond.
Collectors and jewelers buy nuggets as precious gemstones, favoring specimens with particularly nice shapes or colors. Most nuggets are between 85 percent and 95 percent pure gold, but the remainder can be one of several kinds of minerals. Nuggets in laterite can be either reddish or black; nuggets in quartz appear cloaked with white. Any nuggets not deemed to be "jewelry-grade" get melted down and sold as pure gold.
Nugget hunters (who "nuggetshoot" with metal detectors) dream of making finds like the 182-ounce Anvil Nugget, found a 100 years ago in the area around Nome, Alaska, the finish line for this year's Iditarod race. The biggest gold nugget we know of is the Hand of Faith, an 876-ounce (61-pound) behemoth discovered with a metal detector in 1980. The Hand of Faith sits in the North Tower of the Golden Nugget casino in Las Vegas, which claims that it's worth "at least $425,000," or about $485 per ounce. Apparently the value-by-weight of nuggets declines when they get past a certain size: There simply aren't enough people who can afford them.
Explainer thanks Toni Logan of Oxford Assaying & Refining Corp., Jennifer Athey of the Alaska Department of Natural Resources, and the staff at Iditarod headquarters.