Gemfields' main producing assets are the Kagem emerald mine in Zambia and the Montepuez ruby mine in Mozambique. The company has a controlling interest in other mining and prospecting licences in Ethiopia and Madagascar.

The company said its reason for listing was to get access to greater liquidity and international investors.

"The AIM listing will provide Gemfields with access to much greater market liquidity, as well as a widening of the current investor base," said Gemfields CEO Sean Gilbertson.

Various other mining companies have opted for a London listing in the past year or so, including several from Canada, Australia and South Africa - all of them citing similar reasons, and in some cases concerns about the shortage of liquidity in their home markets.

Coloured gemstones have been selling better than diamonds, according to research published by Edison in September. However, Zambia's decision to slap a 15% export charge on gemstone exports has hurt investment.

Johannesburg-listed Gemfields (GML) shares were trading at South African R190 on Friday, up from R180 a year ago.