You never thought you'd see the day, but ivory is back in fashion – mammoth ivory, that is. According to the International Union for Conservation of Nature, mammoth-mining is big business in Russia. Tusks from the long-gone species are being reclaimed from their mass graveyard in the Siberian tundra, and each year 60 tonnes are exported to China, home to the world's largest ivory market.

Aside from being worth significantly more than elephant tusks, mammoth ivory is being touted as an ethical alternative to the illegal poaching trade, which persists in threatening the conservation of the living species. Michelle Obama is one fan, and has been seen wearing Monique Péan necklaces sculpted from mammoth tusks.

But are they really an ethical alternative? With an estimated 150m corpses under the permafrost, stocks are unlikely to run out soon, and thanks to global warming (every cloud . . .) they are becoming increasingly easy to reach. Meanwhile, a report in the Pachyderm journal offers the ringing endorsement that mammoth ivory could "reduce demand for elephant ivory from Africa. Probably."

On the other hand, experts are warning that illegal products are getting mixed up with the pre-historic stuff. You could go by colour, but poachers have apparently been colouring elephant's tusks to make them look like mammoth's. So other than a prominent label on your jewellery, perhaps the only way is to make sure there are still traces of mammoth wool clinging to it. Call it exhumation chic.

Luckily ivory lends well to inscriptions, and it seems apt to go for something eco-conscious. Why not this recent slogan from Save the Elephants? "All ivory, even if legally sourced, fuels the ivory trade."

• This article was amended on 28 September 2010. The original said that 60m tonnes of mammoth ivory are exported annually to China. This has been corrected.