But this is not a precious mineral nor an outlawed drug; it is eagle remains.
The problem is not a new one, but by some accounts it is getting more acute. Eagle feathers, especially those of the bald and the golden eagles, are sacred to American Indians and are vital to their ceremonial dances and religious rituals. But getting hold of them - at least legally - is not easy.
America's eagle-feather underworld was highlighted last week when federal agents, after a two-year operation, arrested eight Indians in New Mexico and charged them with trafficking in dead eagles, hawks and owls.
Last month, a Wisconsin court convicted two men of shooting a single bald eagle and selling its carcass for $400. The poachers were sentenced to nine months in jail.
Although many species of eagle in North America have staged a comeback in recent years - the bald eagle population has recovered from a low of about 800 in the early 1960's to about 12,000 today - demand for their carcasses, and more specifically for their feathers, far outstrips supply.
Under US law, American Indians alone are allowed to own eagle feathers because of their ceremonial and religious importance.
The only legal supplier, meanwhile, is the US government. It operates an eagle cool-storage facility in a suburb of Denver, which is called the National Eagle Repository.
The Repository, recently built on the site of a disused chemical weapons arsenal, cannot cope, however. Roughly 900 birds are sent to it each year by federal wildlife agents; most of the birds are victims of road traffic or have been electrocuted by power cables. But requests from tribes for whole carcasses number about 3,000 a year. The Repository must respond to requests from anyone who is a member of a federally-recognised tribe.
Overwhelmingly, the orders are for whole birds, with about 200 tribes regularly using carcasses in their rituals. Ask for a carcass, however, and you will have to wait two years before the bird, wrapped in clear plastic, will finally be sent to you
In another case in New Mexico, which is due to go to trial next month, an American Indian charged with shooting an eagle out of the sky, Robert Gonzalez, will use the long delays in getting the birds legally as part of his defence.
"I can imagine the outcry if all Bibles had to be ordered in advance," his lawyer, Peter Schoenburg, told reporters.
Gail Evans, also defending Mr Gonzalez, added: "Even when you plan years in advance, the bird still comes months after the ceremony, which is devastating to Native Americans".
Indians, however, are not alone in their search for rare feathers. Last week's arrests in New Mexico allegedly involved feather traders whose customers were not Indian tribespeople but tourists, collectors and businesses.
The feathers were used for making Indian crafts like fans and dolls. A single eagle tail used for this purpose can fetch $400 (pounds 240), the agents said. A completed, double-train Indian war bonnet, meanwhile, can go for as much as $20,000.
In their two-year investigation, federal agents posed as traders on several Indian reservations in the Southwest.
They found evidence at one reservation of some 60 eagles either having been shot or caught in snares with steel traps, and baited with the bodies of dead cows.
One man, who has been arrested and charged, told of how he would sit on the eagles once they were trapped and put his thumb down their throats to suffocate them.Reuse content