Am I getting scammed? 2.5k for 1.5ct Lab MQ

I went to a jeweler to look at diamonds for an engagement ring. Found a lab grown 1.5 ct, F, VS1, marquee cut and was quoted 2.5k for just the diamond. I have the GIA number and looked it up and it says 650 is a fair price. I do not really know how jewelry works so I would like to know if this is a normal mark up.