I am confused. Is this a single diamond or little diamonds with a total weight of 1.85? That makes a difference. All I can tell you is that many insurance appraisals are extremely over valued. I just had this happen to some earrings I sold my mother. I paid $2700 and her insurance appraisal was $7500. Insane? Yes.
I would ask the person who did the appraisal. Was the appraisal performed by the seller?
Yes, the value seems high for I3 three pointers. Did I read 40 grams on your description? Does that include a chain?