An elderly jeweler once told me that as far as he was concerned, diamonds were made for sellin' not buyin'. Unless the stone is a one of akind rock in size, cut, clarity and color, most jewelers will offer a good bit below wholesale if anything at all. They buy "guaranteed goods" from their suppliers at preset (by DeBeers) prices and it would shock most folks what they pay for stones and what the mark up is.
For example, I bought my lovely bride of 37 years stone for her engagement ring from a retired USAF Senior Master Sgt, that had lived with a family of diamond cutters in Antwerp during WWII. He remained good friends with the family and as late as 1980, they would send him stones to distribute to verious "houses" in the SouthEast. Henry could purchase any of the stones he wanted for "house" price. When I told him I was shopping for my wife's stone, he pulled out a 3 x 5 in file card box; flipped it open and showed me about 2 1/2 inches of diamonds! I picked out a .8 carat bluewhite stone that would have graded VVSI and paid 350 dollars for it. Had the stone set in a nice solitare setting and it appraised at, for insurance, at 3,100 1969 dollars!
Pax Christi
Rev. Joel+