Hi I am planning to buy diamond for engagement ring but not sure if this is good price. It's a GIA cert diamond. 1.51 ct , colorD, clarity vs2, cut excellent for $12,000 . Sounds and looks good to me but I am not an expert.
No to #4 - flatty and VG cut … and frankly also no to #5. When you have this size budget, and other vendors who can supply images, there's no reason to buy blind.