Fist-Sized Opal On Auction Block

SYDNEY, Australia - The world's largest opal, a fist-sized gemstone valued at more than $777,000, will be auctioned Feb. 27 in Hong Kong.

Halley's Comet, a 1,982.5-carat black opal found in northern New South Wales, is part of an opal collection expected to sell for more than $6.1 million.

The stone, which is about 4 inches high and 2 1/2 inches across, has a pure black exterior with a blue, green and orange streak, giving it a cat's-eye effect. It weighs almost 14 ounces.

The opal is owned by a syndicate of the six people who found it in a field in the town of Lightning Ridge in 1985, the year of the return of the comet that gave it its name.