proportions - flourescence 20% off?

[boomer]

In comparing two diamonds of pretty much the same cut I have a choice between no flourescence and strong flourescence. The colour of the diamonds is G

The dealer with the ''no flourescence'' diamond mentioned that strong flourescent diamonds with colour G should be discounted by up to 20%. I am not sure whether he is telling the truth given that I had previously never heard of flourescence being one of the 4C''s!

Please help

 

[valeria101]

That 20% is rather hefty. No, fluorescence is not one of the C's. It does affect color (compensating somewhat for the tint in lower color grades whenever available lighting has a strong fluorescent component: such as sun light or some office lighting) and it surely affects price. Very few diamonds with very strong fluorescence may appear hazy due to it: about 98% chances are that your stone with "strong fluo" will not show anything unless yeu olace it under dark lights. You should expect a discount, but % is not the best way to describe it (% of what?). The stone may be a great deal and surely worth a look. Fluorescence is not necesarily a detraction: unless you hate that blue glow during ocasional dispaly in a club or such... There are a few cool pics of fluorescent diamonds in older threads for you to search, if you so wish.

 

[pqcollectibles]

Strong Blue Flour does discount D/E/F and G (? not sure about G) color diamonds. The discount is a sliding scale. As the color drops, so does the discount. 20% seems high for the colorless range discount. I've seen a chart but don't remember the actual numbers. Blue Flour actually adds a premium in lower color diamonds. As Val mentioned, blue flour conter balances "yellow" to make lower color diamonds appear whiter than their actual color grade.

The presence of Med and Strong Blue Flour in colorless and G/H color diamonds gets a bad rap because it CAN cause a diamond to appear milky looking in direct sunlight. Emphasis on CAN. Each diamond has to be evaluated to determine the impact on visual performance medium or strong blue flour has in that particular diamond.

 

[mdx]

If the strong blue does not cause a milky effect and less than 5% do, then a premium should be charged on a G color as it will usually considerably enhance the color.

Johan
Melbourne Diamond Exchange Ltd

 

[Choon]

Hi well this is my first post and i hope i can contribute something here. Yes you are right to say there is a discount off Rap prices if there is some FLOR on colourless diamonds (D,E F ) but if you are talking about I,J and below the more the better as it actually mwke the yellow tint less visible.

Actually its all up to personnel preference here. i have customer who only look for strong to medium blue E, F colour cos they just love the blue thingy.

As for the discount of 20% i think its not true as mention.

 

[fire&ice]

Sounds like the vendor with the non blue fluor stone is trying to scare you.