I agree, he asked, so of course you should tell him what you wanted!
My ex has bought me nicer things now than he did the last few years of our marriage. In the past 2 years I have gotten a $250 fountain for the flower garden, a $150 tree for the back yard, a silver chain, ceramic tile flooring for my basement entryway, etc etc. I would never say, "No I can't accept this" because even though exH paid, it was all gifts from the kids. So just be glad you have a beautiful necklace. I still wear the three-diamond pendant that my ex gave me as a re-commitment gift after the first time he cheated. Because regardless of the outcome, it is a pretty necklace! Good job in your classes.
Good job in your classes.