According to the Rapaport Group, the RapNet Diamond Index (RAPI™) for 1-carat polished diamonds decreased 2.4% in April. In May, the index dropped from 7,543 at the start of the year to 7,159. While the RAPI for 0.30-carat diamonds exhibited some consistency, other sizes were likewise weak. Smaller item costs decreased, reversing their rising trend.
Slow demand in the two biggest markets for diamond jewellery, the US and China, is what caused the decline in diamond prices.