After some negotiation, I have managed to arrange with Zoara to host some some live diamond prices on the website.
These contain the essential information needed to asses a diamond price.
Shape Carat Cut Colour Clarity Depth Table Symmetry Polish Report Price
There are around 14 thousand diamonds of every shape and size, cut, clarity and so forth listed so you are sure you find the type of diamond you are looking for and can see the sort of price you would be expected to pay. These are good prices compared to many jewelers but I do encourage you to shop around of course, ensuring you are comparing apples with apples (or in this case diamonds with diamonds).
I am now working on upgrading the page to give such things as a choice in how many diamonds per page is shown and also selecting by category, such as size, cut, price etc.
Price of Diamonds