UPDATE 1-Gemfields first-half revenue dazzles on higher prices
* Revenue jumps 137 percent to $65.7 mln * EBITDA falls about 8 pct to $18 mln * Shares down marginally By Karen Rebelo March 3 (Reuters) - Precious stones miner Gemfields Plc's revenue for the first half more than doubled as demand for its emeralds mined in Zambia grew a
