I need some help. I have had the same marquise cut diamond for fifteen years. The diamond has VS2 clarity and H-I color. When it was purchased it was appraised at $4,000. I am thinking of trading it in and the jeweler is offering $2,800 on a trade in for a 1.5 carat SI2 with J color or $4,000 on a 2.75 carat with SI1 clarity and J coloring. This is my first time on Pricescope and in reviewing the prices it doesn''t seem like this is that great of a deal. Can anyone help with the information I have provided? THANKS!!