NEW YORK–(BUSINESS WIRE)–Polished diamond trading was seasonally slow in July as the US wholesale market closed for summer vacation. Polished prices softened as midstream inventory levels increased due to the slowdown in demand and increased supply. The RapNet Diamond Index (RAPI™) for 1-carat, GIA-graded, RapSpec A3+ diamonds fell 0.7% during July, and was down 3.2% since the beginning of the year. RapNet Diamond Index (RAPI™) JulyJul. 1, 2017 – Aug. 1, 2017 YTDJan. 1, 2017 – Aug.