On floursence, remember that it accounts for only a small portion of the variance. It is really unimportant as compared to other factors, but it is a way of casting aspersions on someone else's stones, if you are into that sort of thing. There was a nice piece on flourescence in Gems and Gemology a couple of years ago. As I recall, it came to the opposite conclusion: blue flourescence in faintly yellow and lower stones would improve the color--that is they would appear white when flourescing, but in white stones the advantages of blue flourescene were not siginificance and the milkyness was an issue.

Fluorescence can be an attribute or a hindrance depending on its severity and how its presented. Extreme fluoresence can make a stone look weird, I've heard it called greasy, but milky is probably a better discription, In a high dollar stone even moderate reaction is probably not good, as you may be competing against another jeweler basically on the cert. Cert vs cert cutomers can get pretty picayune, probably against their best interest(its better to 'see' the stone, not get all hung up on minor specs). On the other, hand moderate fluoescence can perk up a budget stone, making it appear a little better than its color spec would suggest, with the right customer this equates to more bang for the buck.

From the GIA website... www.gia.edu/library/4286/6285/faq_detail_page.cfm What is fluorescence? Is it something I should be concerned about? Answer: Fluorescence is a phenomenon occurring in diamonds and other gemstones. The fluorescence that occurs naturally in a diamond arises from submicroscopic structures within the diamond when it is exposed to UV light. Blue is the most common color of fluorescence, but others colors are also possible. On our GIA Gem Laboratory diamond grading reports, the strength of the fluorescence is noted as none, faint, medium, strong, or very strong. Beginning with medium, the color of the fluorescence will be noted (ex. blue, yellow, green, etc.). If fluorescence is faint, the report will not note the color. Blue is the most common color for a diamond to fluoresce. GIA has extensively researched the subject of fluorescence and we published a detailed article describing our findings in the Winter 1997 issue of Gems & Gemology, entitled "A Contribution to Understanding the Effect of Blue Fluorescence on the Appearance of Diamonds." Some jewelers believe that fluorescence is always an undesirable characteristic. However, GIA's research indicates that fluorescence is not necessarily negative, and in some cases, fluorescence actually has a positive effect by making a diamond appear whiter. The publication is here... lgdl.gia.edu/pdfs/W97_fluoresce.pdf

I went to know what fluorescence and it'S USE