LONDON (Bloomberg) — Bermuda-based TanzaniteOne Ltd., the world's largest tanzanite miner, said it had been granted a "staged" exemption from Tanzania's prohibition on exports of rough tanzanite larger than five carats, or one gramme.

The company will be given a moratorium allowing for 100 percent export of its production, including stones in excess of five carats until December 31, TanzaniteOne said in a statement yesterday.

The government also indicated the company will be given a "rollout period" to enable expansion of its local cutting and polishing facilities in Tanzania, TanzaniteOne said.

The rollout will be staggered to guarantee a consistent supply of gemstones and ensure no backlog of high value, uncut stones, it added, without elaborating on the period.