by appreciate_the_help » Apr 15, 2019 Need some help understanding what to look for when it comes to a lab-grown diamond's "4C" lab report. GIA and AGS don't seem to really be players in this arena - so which labs DO offer reports and which ones are actually credible? Cost is always an issue. Do some laboratory reports cost more than others? Why? Should I look for a report that has more than the basic "4C" information? (Things like light?) Thanks!