Colour

Diamonds come in a range of Colours, from totally Colourless to tinted. The most rare and valuable Colour is the highest and whitest, Colour D. Colour however is a personal choice, a lower Colour that isn't as valuable is still just as good in quality as a higher Colour if the Clarity and Cut is the same. Some natural Fancy Coloured diamonds, eg: Intense yellow, pink, blue, red, etc can be much more valuable than the whitest diamonds. Natural Fancy Colours are not classed as low Colours. The lowest Colour is a personal choice. The lowest Colour to stay true white is Colour H. Colour I is a commercial white, Colour J is slightly tinted but can still look white or whitish. I and J Colours may still be OK for white diamond shoppers. People who demand the finer whites should start looking from Colour G and above.

Fluorescence

Diamonds can have nil, slight, medium, strong or very strong Fluorescence.

Fluorescence when strong and very strong can make Colour of diamond appear different under certain types of lighting. Some people like this but most prefer nil and no higher than medium. Blue Fluorescence will make Colour look whiter, especially if it's a low Colour. A yellow Fluorescence will make Colour look lower, especially if it's a high Colour.

Do not take Fluorescence into account if graded nil, slight and in most cases medium. Negligible Fluorescence usually cannot be seen with eye and is nothing to worry about. Fluorescence is not necessarily bad. In some cases it can be advantage, eg: Budget restricts that you buy a low Colour diamond, but you prefer a higher Colour. Strong – very strong blue Fluorescence will make diamond appear whiter, but beware sometimes it can also make diamond look milky – so you should see the diamond first or buy from a reputable source that will advise you correctly.