Martin Rapaport, founder of the world's largest diamond-trading platform, will this week begin the open diamond tenders that will pave the way for a regulated futures market by the start of 2009. But his main rival says it will not work.

The four-day auction that starts today marks the start of the monthly internet-based sales of individual stones that Mr Rapaport's New York-based company hold. Data from these tenders will form a pricing index from which he plans to develop diamond-based futures contracts overseen by the US Commodity Futures Trading Commission.