If by any chance you have Chinese snuff bottles on your mantelpiece, chances are you already realise how valuable they can be. But if they are not Chinese, they may not be worth a lot.

New York-based Mr Michael Hughes, vice-president of Christie's and senior specialist in Chinese works of art, explains that the Chinese snuff bottle auction in London on October 4th is timed to coincide with none other than the annual International Chinese Snuff Bottle Society Convention. "They take them very seriously, these snuff bottle collectors," he says.

Snuff bottles come in jade, wood, porcelain, enamels, glass and agates and they constitute a "miniaturisation of all the various forms of Chinese art which is what makes it appealing to a certain audience", says Mr Hughes. Snuff is basically tobacco mixed with spices, taken up the nose. The Jesuits, who were at the court in Beijing, introduced snuff to China. They gave it as gifts to the emperor, so it became an imperial and courtly tradition. Once it took off at the imperial court, snuff-taking became popular with the masses. The earliest bottles are mid-17th century and are mostly imperially marked. By the 19th century, there was mass production of snuff bottles in China.

Snuff could stay dry in snuffboxes in Europe, but humidity in China required some kind of a corked vessel to keep the damp out "so the snuff bottle came about ultimately as a Chinese design", he says.

The record price fetched for a snuff bottle is more than $400,000 (#382,484). "The most we've sold a snuff bottle here in New York was $210,000 and that was a few years ago," he says.

Most snuff bottles are just vessels, not figurals, although a Japanese horn figural bottle in the forthcoming sale is estimated at £5,000 to £7,000 sterling (#7,599 to #10,638).

A rare aquamarine bottle, circa 1780, is estimated at £18,000 to £30,000. Many aquamarine bottles date from the 1960s. If dated earlier they are generally from 1850-1900.

A cylindrical bottle, a fine 18th century yellow jade, is estimated £3,500 to £6,000. A shadow bottle - "we call it shadow because it looks like the shadow of a figure" - depicting the Daoist figure of Lui hai, the god of commerce, with his mythical three-legged toad is estimated at £9,000 to £12,000.

Mr Hughes describes as "a total beauty" a rare shadow agate bottle of semi-transparent misty-grey stone with a natural vertical inclusion suggestive of calligraphy, estimated at £6,000 to £12,000. "There's a bird carved either on a tree branch or on a rocky mossy bank. It's difficult to be sure. But below it are natural moss-like inclusions which actually look like you would find on a Chinese painting. It's truly unique."

A rare translucent rock crystal coin bottle, 1781-1810, carved in the design of a Spanish eightreales coin with the royal coat of arms on one side and the portrait of Charles III on the other, is estimated at £3,000 to £4,000.

He describes another transparent rock crystal bottle, circa 1770, as "a beautiful thing. It's almost like holding a balloon in your hand" it's so light (estimate £5,000 to £7,000).

A fine celadon and russet jade bottle, 1740-1790, carved in low relief with ruyi-shaped clouds above breaking waves is estimated at £12,000 to £18,000. Says Mr Hughes: "The russet part of the stone is on the narrow side and those narrow sides are carved with chilong (small dragons). They're carved on the shoulders and down the narrow side. The larger face of each bottle is actually green. You've this lovely transition from a green bottle to a brown and the brown is cleverly used to depict dragons."

Readers can contact Mr Hughes in New York. Telephone: 001 212 636 2176.