Personally for my family and close friends I buy the biggest, brightest, whitest, eye clean diamond (with some blue fluoro); usually D-F, SI1. You may not be as worried about high colour and G-H will save you some money.
You can see the impact of cut, colour and clarity from the small chart Carat weight costs the most, especially “Magic Weights” (like 1.00ct, 2ct, 1/2ct etc). “Undersizes” like 0.90ct and 0.45ct cost a lot less but it is hard to find good stones. There are about 20 times more 1.00ct diamonds than 0.99ct stones.
If you are shown 2 diamonds, one top D and Flawless and a G VS2 or SI1 you will probably think “They both look the same to me, but one costs 2 or 3 times more. Are you kidding me?” So who buys the D Flawless? Really rich people and those hiding corrupt money. D IF diamonds are ‘fungible’ – no one needs to see the diamond – they can be sold overnight to dealers by emailing them a grading report.
D IF have been called ‘Investment Diamonds’ but their prices go up and down based on global markets. For example prices rose when Russians became rich, and then Chinese demand held prices high. However demand and prices have fallen with Russia’s oil prices and the recent crackdown on corruption in China and India. There is always demand for ideal-cut D-H, VS-SI diamonds because they look as good and cost less.
If you want an investment diamond then go to www.HollowayPinkDiamonds.com.au