Perfume bottles can be worth thousands of pounds with some 70 bottles in a forthcoming London auction estimated to fetch from £1,000 (€1,683) to £15,000 sterling each. All 70 lots are expected to fetch around £250,000.

Mr Daniel Gallen, specialist in 20th century continental decorative arts at Christie's, says the most valuable perfume bottles tend to be by French art nouveau jewellery designer Rene Lalique (1860-1945).

"You do get perfume bottles by other makers that can fetch a lot of money but the ones that we sell here at South Kensington tend to be the Lalique ones. They are really the most sought after and the rarest. And the most unusual of the Lalique ones can make a lot of money."

Lalique started designing perfume bottles from about 1907, initially for a French perfumier, Francois Coty. He subsequently designed perfume bottles for about 50 others and his own Maison Lalique. "A lot of the most desirable ones today are ones that he made for his own house," says Mr Gallen.

Although produced in some quantity in the 1920s and 1930s, some are very rare today. They vary in size from between five centimetres high to about 20 centimetres high.

The tiara stoppered scent bottles can be particularly valuable. For example, Bouchon Cassis, a scent bottle with a tiara stopper in blue frosted glass, circa 1920, in the forthcoming auction is estimated at £7,000 to £9,000 sterling.

The most expensive bottle in the sale is called Bouchons Mures, a clear and enamelled scent bottle with a mulberry tiara stopper in blue frosted glass, estimated at £10,000£15,000.

"There's another very interesting one called Au Coeur des Calices, a blue frosted scent bottle modelled as a single flowerhead with the stopper formed as a wasp," he says. (Estimate £4,000£7,000.)

Most Lalique perfume bottles should be signed either Lalique or R. Lalique. However, Lalique is still in production and they bring out a perfume bottle every year. It is the 1920s and 1930s bottles which tend to be of most interest to collectors, he says.

"If somebody has a perfume bottle and it's marked Lalique they can send in a photograph to an auctioneer. A professional needs to have a look at it to determine the age and value of the piece."

He believes that the world record for a Lalique perfume bottle is for a Bouchons Mures bottle, which made £38,000 sterling in 1990. Asked why a similar bottle in the forthcoming auction is estimated at £10,000 to £15,000, he says: "Basically, 1990 was the height of the Lalique market so the prices that would have been achieved then would be higher. Prices are starting to go up again now.

"But after 1990 prices dipped substantially along with the stock market crash and the fact that Japanese buyers weren't buying so much in the early 1990s. But now prices are starting to rise again."

Ms Grainne Pierse, proprietor of Courtville Antiques in the Powerscourt Townhouse Centre, Dublin, deals with the Victorian double-ended scent bottles. "They generally have one end for scent and the other end may have had a little vinaigrette - a pierced grid with an impregnated sponge with smelling salts.

"They're precious little items. They vary in shape and colour. Those are the two very important things when you're collecting them. You get very vibrant coloured glass, for instance, brilliant turquoise, Bohemian red glass or ruby glass. They vary from about £100 (€126) up to maybe £500 or £600.

Readers are welcome to approach either specialist for valuations.

Ms Grainne Pierse: Telephone: 01 679 4042.

Mr Daniel Gallen: Telephone: 0044 207 321 3120. jmarms@irish-times.ie