In traditional Chinese medicine rhino horn was ground into a powder or shaved, added to boiling water and taken as a "cure" for a range of illnesses from arthritis to fever. Considering rhino horn is precisely the same material as your nails - keratin - you might just as well chew your own fingers.
In the past couple of years some of the respected colleges of traditional medicine in China have come out saying that there is no scientific evidence that rhino horn has any curative or restorative value. Slowly its use was dying out.
But a few years ago an urban myth spread around Vietnam. A never-identified VIP - sometimes a general, sometimes a minister - was supposedly at death's door, his doctors having given up hope. Then he started taking rhino horn and made a miraculous recovery.
And even though no one has ever identified "the star" of this story, suddenly rhino horn became a fashionable product not just as a "medicine" but also a hangover cure for the newly moneyed fashionable set. It showed off their purchasing power and had the added edgy appeal of being illegal.
And so the slaughter of South Africa's remaining rhino leapt from a few dozen in 2008 to several hundred by 2011 and around 1,200 over the past three years. Every night in the Kruger National Park, home to the world's largest population of rhino, two or three animals are shot by poachers.
As the demand from China and Vietnam grew, so the price rose. A kilo of horn sells for between $30,000 and $60,000 on the black market as it passes from dealer to dealer and on to the consumer. Cut into bangles or bead bracelets the price per kilo is cheaper. Horn is carved into cups and highly ornate libation bowls. Most expensive of all are the statues carved out of whole front horns, which can weigh upwards of 6 kilos and cost more than $250,000.
None of that is new. Antique carvings and cups dating back to the 16th century regularly come up at auction and easily fetch prices upwards of $100,000. The auction house Christie's sold one for almost $500,000. Horn, just like ivory, has long been prized as decorative proof of status and wealth. The difference is that even at the turn of the century there were tens of thousands of rhino across Africa and Asia.
Of course the closer the rhino comes to extinction, the more horn becomes a scarce resource with the inevitable hike in price. That in itself has created a new market in horn, to buy and keep, as an investment for the future.
It is no longer anything to do with any supposed curative powers. It is now just about hard cash. As well as the wealthy buying horn, analysts and law enforcement agencies say that horn is traded between criminals as payment for other illegal deals such as drugs and weapons. Rhino horn has moved from a conservation issue to a major commodity for organised global crime syndicates.
On the legal side, the owners of private rhino farms in South Africa have amassed stocks worth millions of dollars from the horns of rhino that have died naturally but also from periodically cutting the horns down to a stump. The horns can slowly regrow.
John Hume, who owns the largest private herd of rhino, has an estimated stockpile of five tonnes of horn. He and other "pro-trade" farmers argue that they are protecting their animals from poachers. They also believe that creating a legal market in horn would put the criminal syndicates out of business.
Their hope is that in the future the ban on trading horn will be lifted and they can sell their stocks.