TanzaniteOne, AIM-quoted miner and marketer of rare brilliant violet blue tanzanite stones from near Mt Kilimanjaro in Tanzania, says it has discovered 'the world's largest piece of rough tanzanite'. The stone, found 270 metres below ground at the company's Merelani mine in northern Tanzania, weighs 16,839 carats, more than three kilograms, and the company expects to produce several gems from it.

Spokesmen for Bermuda-based TanzaniteOne say rough tanzanite prices can range from $200 (£117) to $2,000 a carat. This suggests significant potential value for the stone, which the company has decided to name 'Mewenzi', after Kilimanjaro's second highest peak, claiming 'Uhuru', the name of the highest peak, is being reserved on the off-chance of finding an even bigger stone.

Run by entrepreneurial chief executive Mike Nunn, tightly-held TanzaniteOne was floated on AIM a year ago by broker Williams de Broe at 42p. Up 11p this morning to 95.5p, the shares are still a potentially attractive punt on the appeal and rarity value of the stones.

Tanzanite One	AIM	£17.28m	23.50p	0.00p
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Other company articles:
Tanzanite mans the barricades			05/11/2008
Tanzanite removes director			31/10/2008
Tanzanite builds its defences			27/10/2008
Gemfields returns to Tanzanite fray			21/10/2008
Gloves off in gem bid			25/09/2008