The lady with the brooding hollow eyes - the Ivory Mask from Benin - is everywhere: on bronze brooches, on toilet paper rolls, on street light decorations and in copies at the National Museum of Nigeria.

The original mask - of which there are four known copies - was chosen by the Nigerians as the symbol for the Second World and Black African Festival of Arts and Culture. Attempts to retrieve a copy of the mask from the British Museum, even on loan, failed.

Negotiations for the return of the masks are part of the growing international movement to return works of art that were taken from countries of origin during the colonial period. So far, successful restitutions have been arranged between Belgium adn Zaire and between Holland and Indonesia.

The mask, which has been described as one of the most beautiful pieces of ancient African art, was taken from the royal palace at Benin City during the British punitive military expedition of 1897. It was found in a wooden crate and taken as war booty.

The Oba, or king, of Benin City would have used the mask, and others like it, during annual celebrations of his regime. He would wear the mask, slightly larger than nine inches, around his waist while he danced to dismiss unfriendly spirits.

The four copies of the mask have been dated to the first half of the 16th century. The one chosen as the festival emblem, thought to be the finest example, is on permanent display at the British Museum in London.

The others are in the Metropolitan Museum in New York, formerly in the collection of the Museum of Primitive Arts; at the Katherine White Reswick Collection in Los Angeles, and in a private family collection in England.

Efforts to retrieve the mask from the British Museum became highly charged issue at the UNESCO General Conference meeting last year in Nairobi, Kenya. The Nigerians put forward a resolution authorizing the Director-General of UNSECO, M. A. Mathar M'Bow, to use his "good offices" to appeal to the British government to return the mask in time for the festival.

However, the Nigerian delegation subsequently withdrew the resolution before the vote, feeling that such international pressure would hamper negotiations with the British Museum. A more general resolution, following previous UNESCO and United Nations' resolutions, was passed 66-0, with nine abstentions.

This resolution calls for an international committee which, armed with an international instrument such as a recommendation, would bring member states together for bilateral negotiations on the issue of restitution.

While the Nigerians, with the support of other African governments, proceeded with efforts for general restitution, the International FESTAC Committee made an appeal for a loan of the Ivory Mask from the British Museum.

British Museum officials said they decided against lending the piece because they felt that the 400-year-old mask is too fragile to be transported. John Picton, a curator of African art at the British Museum's Museum of Mankind, said in London that the Ivory Mask is badly cracked on the inside as well as on the surface.

"We don't know what the ivory could do," he said. "It could split. It is very sensitive to the atmosphere." Lagos, he added, has a different environment and different humidity than the original home of the mask in Benin.

However, the Nigerian press reported that the British government had asked for an indemnity of two million Naira (about $3 million), which the International FESTAC Committee was unable, or refused, to meet.

When it became clear that the government could not retrieve the original mask from the British Museum, the Nigerian Federal Ministry of Information and the Bendel state governor each commissioned artist from Benin to replicate the mask.

One of the new masks copied from a British Museum postcard was hailed in The Daily Times of Lagos as "magnificent."

"It is even better than the old mask, which has been haunting our sleep and disturbing our waking hours," wrote Chukwujindu Nnite. "We just have to look at the old one and applaud the splendor of its finesse. Get attached to it emotionally, as though it was the breath of our nostrils, for what we have we hold."

Felix Idubor, an artist commissioned by the Ministry of Information to make two copies of the mask for the National Museum, spent 40 days and "a lot of sleepless nights" working on the replicas with the help of three assistants.

The ivory, which he brought from the village of Azia, was so hard that he often had to apply undiluted palm wine to it in order to carve it. "It may look fragile," he said, "but it is very hard. Italian marble stone is easier to carve than ivory."

Idubor said the prestige of art in Nigeria has increased greatly since the British government insisted on the indemnity for the original mask. "People have laid more value on art work in Nigeria since this is a controversial issue," he said.

Although he has been to London, Idubor said he never has seen the original mask, which caused him some problems in reproducing it. "You don't see the back or the hair, only the front view on the postcard," he said. "You have to put in a lot of imaginations."

He praised FESTAC organizers for choosing the mask as the festivals emblem. "When you have a thing like this, you want a simple object to represent it," he explained. "You have beautiful tiger inlay and bronze objects in Nigeria. But with its simplicity and the material and perhaps the age, I think the mask is an ideal."