Company sees revenue spike at US$65.7m in last six months of 2013.
Federation says dealers should be responsible for what they sell.
Brit designer travels to Africa during creation of spiked neckpiece.
But miner says future is bright with growth opportunities in sapphire.
Stones from TanzaniteOne to move through Chow Tai Seng.
Diamond company buys 25% stake in auction service biz Curtis Fitch.
Consumers now able to purchase stones directly; store a member of RJC.