Cut – This is the most important and it isn’t just about the shape. Cut refers to how light travels through the diamond. How light refracts off the facets. If the angles and dimensions are near perfect.
Colour – the scale of lack of colour starting at “D” and travelling down. The misconception is that the “I” colour the diamond is yellow. Some diamonds have a grey or brown hue
Clarity – The internal inclusions. This is the most contentious and difficult to properly understand. Most natural gemstones and of course diamonds have internal inclusions microscopic in fact. For anything, SI2 clarity and above you need at least 10 x magnification to see it, and it only applies to looking down directly at the diamond. Internal inclusions do not affect how the diamond sparkles or washes out the colour.
Carat – often mistaken for a dimension, carat is a weight measurement. On certain diamonds (like Emerald or Oval cut) the diamond is shallow, which makes the diamond proportions from the top look a lot bigger. As they are diamonds that don’t sparkle like a round brilliant cut, it is ok. For every 0.25 carats the price of diamonds goes up, so the best values are just below the 0.25 ct intervals.
Certification – GIA is the best known of the diamond grading laboratories, but equally of note are IGI and HRD in Amsterdam, and our own GSL and DCLA laboratories in Australia. Certified diamonds and especially GIA certified diamonds carry a premium on them. IGI and HRD are cheaper alternatives, being European based they look at diamond colour differently from GIA
Cash – this is another way of understanding your budget and based on looking at and comparing diamonds, how is your budget going to best accommodate the value you have found?
Confidence – are you confident that the person you are talking to about diamonds is knowledgeable and understands where your values are?