The priciest offering at this writing is a $319,999.99 ring set in platinum with a 1.54-carat pink diamond rated with VVS1 clarity. For comparison, a solitaire diamond ring at Tiffany & Co. starts ...

The diamond market was seasonally slow in February, with prices strengthening for round, D to G, IF to VS1 goods in most sizes. Other categories showed mixed trends. Prices were stable for elongated ...