Shedding light on diamond fluorescence

More and more often we are receiving clients who are not only familiar with “the 4 C’s” of diamond shopping, but are also making their preferences known regarding a diamond’s fluorescence. Unfortunately, a lot of the information they have acquired from their own research as well as from diamond dealers is misleading, conflicting and erroneous. So, what exactly is fluorescence, and how does it affect the appearance and value of the stone?

Fluorescence is a phenomenon that occurs in approximately 20% of gem quality diamonds. A diamond exhibiting fluorescence will literally glow a purplish-blue or sometimes a yellow hue when viewed under an ultraviolet (UV) light source such as a black light. It may also be activated when viewed under natural sunlight, a natural UV light source.

This characteristic in a diamond has been widely used to cast aspersions on other dealer’s stones, as well as to overvalue non-fluorescing diamonds. Typically, the dispensed advice takes the following forms:

1. Blue Fluorescence (FL) is bad, stay away.
2. FL in lower color diamonds, e.g.; I-J-K is a positive in that it will make the diamond face up whiter but only if the FL is faint or Medium, not Strong. In higher colors (D-H) it is detrimental; stay away.
3. Strong FL is to be avoided at all costs.
4. FL diamonds need to be priced and sold at a discount relative to comparable carat weight, color/clarity-cut diamonds that are non-FL.

The fact is that FL is not a negative, on the contrary it can be and is a positive factor. Several respected members in the trade have known and advocated this position for years.

In 1997, GIA (Gemological Institute of America) conducted an extensive study on the effects of blue diamond FL on visual perception. Both consumers and tradespeople were asked to evaluate the effects of fluorescence on their visual perception and to note any meaningful distinctions between non-FL to FL blue diamonds of differing FL intensities.

The results of this GIA study were highly instructive and surprising. GIA found that non-trade observers could not make ANY meaningful distinctions between non-FL to the FL blue diamonds and that FL blue diamonds had no overall effect on the diamond’s color or transparency!

The link to this GIA study is here: http://www.gia.edu/pdfs/W97_fluoresce.pdf

This is a very important study and is recommended reading consumers and should be required reading for all diamond and jewelry professionals. The bottom line? There are no grounds to consider blue diamonds in a negative light and therefore no basis for price differentiation relative to non blue diamonds.

(KingOfRocks.com is a Montreal-based online jewellery retailer focussing on quality diamond and gold pieces, offered at reasonable prices and provided with the very best of customer care. )

Oh Rhodium, Rhodium, what for art thou?

“This piece has a rhodium finish” is one of those lines jewellers toss out without much thought, and which jewellery buyers hear and accept without question – even when they don’t know what it means. So, for those of you too shy to ask, here’s all you need to know.

Rhodium is a shiny, white precious metal, in the same family as platinum and palladium, and is most often used in the jewellery business to plate white gold items. Why would anyone want to plate white gold with another white metal? Well, because gold is naturally yellow and is made white by mixing it with nickel or silver or palladium, the resulting “white” gold is actually more of a gray (with a yellowish tint). Also, gold is a relatively soft metal that can be easily scratched. Plating white gold with rhodium gives it shiny white appearance, extra protection from scratching, and a resistance to tarnishing.

Rhodium plating does not last forever. With jewellery items that are worn often or constantly, (think wedding and engagement rings), the plating can wear through in as little as a year. If you notice dull or slightly yellow areas on your white gold jewellery, it is likely that the rhodium has worn through. Replating an item is a quick and simple process for any equipped jeweller. Note though, that replating will not fill any scratches or dents, so be sure that your jeweller polishes and repairs your piece if necessary before the final plating.

(KingOfRocks.com is a Montreal-based online jewellery retailer focussing on quality diamond and gold pieces, offered at reasonable prices and provided with the very best of customer care. )