Definitely have the stone graded by GIA before purchasing. An untreated earth-mined 1.5+ ct FIY or FVY old mine will be significantly more than $6-7k. However, based on the photos you posted, it looks like you prefer to have more brown, which is good for your budget. If you are able to obtain more photos, please request the photos be taken against a pure white background. Do you have other examples of color(s) you like? What aspects make you feel like a diamond is too "new"?