(IDEX Online) - The GIA says it needs to re-assess a number of green diamonds that passed through its labs.It says concerns about potential treatments have prompted it to recall stones submitted for grading between January and June 2020."Recent research and investigation into potential treatment methods caused us to request the return of the subject diamonds for further analysis," said Tom Moses, GIA executive vice president and chief laboratory and research officer, in a statement.The lab has not said how many diamonds are affected or given details of what treatments may be involved.It has written to affected customers, and will not be charging them to re-grade the gems.Pic shows the Aurora Green, a record-breaking 5.03-carat fancy vivid green diamond