The price of polished diamonds declined slightly in May as buyers waited for the JCK Las Vegas show, which took place between 3 to 6 June.
The index found the price of 1-carat, GIA-graded diamonds was flat during the month, while the price of 0.3-carat diamonds fell 1.1% and the price of 0.5-carat diamond slid 0.3%. The price of 3-carat diamonds dropped 1.1%.
During the first five months of the year, the price of 1-carat diamonds rose 1.2% but was still 4.9% below its level from the same time last year.
The monthly report acknowledged that US demand is steady and the country remains the best market for diamond dealers. However, weaker economic trends in a contentious election year is impacting sentiment in the diamond and jewellery trade.
Polished demand is specific and businesses across the pipeline are working with smaller inventories.
The report said the JCK Las Vegas show highlighted “significant challenges” facing the diamond industry in light of the relationship between the rough and polished markets, raising levels of consumer demand, how to sell the idea of diamonds to millennials, rising interest in lab-grown diamonds, and responsible sourcing.
Martin Rapaport, chairman of the Rapaport Group, said: “The diamond industry must establish reliable chain of custody and source certification protocols to ensure that legitimate diamonds from good firms are differentiated from unknown diamonds from questionable sources.
“The industry must be able to answer the question, where do our diamonds come from?.”