Diamond Fluorescence 2011-09-26T21:10:55+00:00

Buying a diamond can be a nerve-racking experience. If you want my expert advice on buying the best diamond just drop me a note and tell me what you are looking for and how much you want to spend and I will get back to you with my personal recommendations for a beautiful stone that fits in your budget. This is a FREE service, doesn’t cost you a dime extra, (in fact I am sure that it almost every case I can save you lots of money) and there is absolutely no commitment.


Not interested in the details?
Here are my simple suggestions regarding diamond fluorescence.

For those buying H,I or J color diamonds try and go with a stone that has Medium Blue fluorescence – this can (but is not guaranteed) to give your diamond look like it has a higher color. Don’t go crazy with this and if you can’t find one go for None or Faint fluorescence. If your diamond is G or higher to start with then go with None or Faint fluorescence as you have nothing to benefit from it.

Want the details on diamond fluorescence? Read on…..


Diamond Fluorescence

Diamond Fluorescence Chart As Viewed in UV Light Courtesy of James Allen


Diamond fluorescence is one of the most hotly debated and misunderstood characteristics of a diamond.  In a famous study the GIA tried to minimize the impact of fluorescence and stated that under normal lighting conditions (more on this below) even a strong blue fluorescence is usually impossible for the average diamond buyer to pick up. If in fact that were the whole story there wouldn’t be much to wright about and nobody would pay much attention to it.  The truth however is not so clear cut.

What is Diamond fluorescence?

Fluorescence refers to a glow that some gems, including diamonds, give off when subject to UV (Ultra Violet) lighting.  This glow can be weak , or faint as it referred to in the diamond industry, medium, or strong.  Now I know you are probably thinking that since you don’t hang out at night clubs you shouldn’t care about this but the fact is that  contrary to the GIA , fluorescence can have a couple of other impacts on your diamond:

1)   As fluorescence gets stronger there tends to be a haziness in the diamond that effects its brilliance. So a diamond with strong blue fluorescence will not seem as clear as the same diamond and light or no fluorescence. (see ont his page how James Allen phrases it)

2)   Fluorescence tends to improve the appearance of diamond color. So a diamond with an H color may look better if it has a Medium Blue Fluorescence. (this is actually referenced in the same GIA study)

Some not so scrupulous sales people actually abused fluorescence in higher color grades, invented a term called blue-white diamonds, and tried to sell them as “better diamonds”. This of course is nonsense and the term is actually banned by US FTC. If your jeweler tries to use this term on you- walk out and find another (my recommendation is to buy online!)

What does this all mean for you?

1)   If you are buying a diamond with G color or better stay away from Medium and Strong fluorescence. You will not benefit at all from its presence but you may very well see some of the haziness I spoke about. (

2)   If you are buying a diamond with H or lower color then you may benefit from a diamond with Medium fluorescence. I wouldn’t go so far as to recommend Strong Blue as in this case the benefit of the color improvement is outweighed by the haziness.

In general these rules apply to those wisely buying online as opposed to in person. Since you won’t be seeing the diamond upfront you these are good rules of thumb that you can use in making your purchasing decisions. If you are buying locally at a retailer (and I personally don’t recommend this since you can save a bundle on line) then go with your instincts and if you find a diamond you like – even if it has fluorescence don’t feel that you shouldn’t buy it because of this.