Overseas Diamonds, a longtime Belgium-based sightholder best known in the United States for the isee2 viewing system, recently filed for the Belgian version of bankruptcy, the company said.

It had been a DTC client since 1981 and also purchased from Alrosa, BHP, and Rio Tinto, among others. It issued bonds in 2006, a move that was hailed as part of a new transparency for the industry.

Sources said Overseas was squeezed by the decline in the rough market and the weak market for polished.

Some people from the company’s U.S. office, now closed, have started a new company, Gembrooke. It will be based in Short Hills, N.J., and market ideal-cut diamonds and jewelry. Joseph Srodawa, former managing director for Overseas Diamonds and the isee2 brand in the United States, will manage it.