What about Fluorescence?

We are frequently asked about what fluorescence in a diamond is, and how it affects pricing.  Well, the simple answer is not quite so simple.  About half of the world’s diamonds production has fluorescence that can be observed under when illuminated with a long wave ultra violet light.

About 10% of the diamonds on the market have florescence that is strong enough to make a noticeable difference between the stone's color in incandescent light which is low in uv light. and in sunlight or fluorescent light which are high in uv.  When a diamond has fluorescence it is classified in intensity as being faint, medium, strong or very strong.  In almost all cases that fluorescence color seen under UV light is blue in color.  this is highly important, as blue fluorescence negates or minimizes the appearance of yellow.

If the diamond being considered for purchase is high color, say a D to G colored gem, it tends to be lower in wholesale price due to the presence of fluorescence.  How much lower that price depends primarily if it has a waxy or somewhat milky white appearance due to the fluorescence.

If the stone is H to I in color fluorescence likely has little or no impact on the gem’s price, again unless it exhibits that waxy appearance.

As the stone’s color grade drops to the J to M in color range the presence of blue fluorescence may have a beneficial impact on the stone’s appearance of color, and may help the stone bring a higher retail price.

When we are looking at loose, unmounted diamonds in our office the stones are typically presented in a small folded envelope called a flute.  These diamond paper flutes are lined with a blue colored paper liner, which makes the gems contained inside appear whiter than they actually are. 

Retail dealers usually show these loose gems on a blue or dark colored felt pad, which also makes them, look whiter.

Ask to see the stone upside down on a folder piece of white paper, with the white paper below and behind the gem.  This is the best way to determine if a stone had body color and if it is a darker or lighter hue that another gem place next to it on the paper.

...
The Gem Guys
E-Mail NEGEMS Homepage NEGEMS

Sapphire Pendant

We wanted to show off one of our latest custom pieces.  This 14-kt white gold neck-piece is mounted with about 1.25 carats of nicer quality, round brilliant cut diamonds to accent the main gem.  The large significant stone is a  5+ carat, very fine quality blue, Ceylon, round shaped sapphire.  The solid pendant is suspended from a hinged bail so that it can be fitted to an Omega chain or a strand of pearls.  In size this stunning piece is just under two inches in length. 
...
The Gem Guys
E-Mail NEGEMS Homepage NEGEMS

Bad Diamond Certification alert!!!!!

NATIONAL JEWELER MAGAZINE in their online publication just provided the following information (03/26/12).  This sort of information is highly important to remember if you find yourself wanting to only evaluate a diamond certification instead of inspecting the gem itself. 

Antwerp--HRD Antwerp announced Friday that it has fired four diamond graders for what the laboratory is calling “an unprofessional act” and is conducting an internal investigation into the matter.

Lab General Manager Georges Brys said on Friday that three of the graders were let go last Thursday and the fourth on Friday. He would neither confirm nor deny reports that the firings were related to bribery.

“We have not made any statements in that direction,” he said.

Brys also denied reports that the police were involved at this point, noting that the internal investigation will indicate whether it’s a criminal matter that will require police intervention.

“They were fired based on the fact that they have made a professional mistake,” he said. “We have not yet any evidence pointing in that direction.”

He said the graders involved had been employees of the lab between eight and 11 years. It’s unclear for how long these “professional mistakes” have been occurring, and it is also unknown how long the internal investigation will take, Brys said.
...
The Gem Guys
E-Mail NEGEMS Homepage NEGEMS

LETTER TO ONE OF OUR CUSTOMERS

Today while going through some old Word documents I ran across an old letter I had written to a customer who had inquired about diamond pricing.  As I reread my letter I though it might make sense to post it on the Blog.  I realize I have blogged about this issue in the past, but I felt the topic was worth revisiting.  Here's the original letter:

OUR LETTERHEAD AND RECIPIENT  DELETED.

April 08, 2010

Hi XXXXXXXX,

Glad you asked about diamond pricing and why some stones are cheaper or more expensive than stones that appear, on paper, to be similar in quality.  The easy assumption is that all diamonds of a given size and quality cost the same, and that some diamond sellers just want to make higher margins.  This obviously is not true, and margins are not the primary reason for the broad price range you find in the marketplace.

You have just finished personally inspecting several 2 carat sized gems.  You saw a variety of quality grades, and some of the GIA graded SI 1 stones you looked at appeared under our microscope to be not as clean as some of the SI 2 graded gems.  Some higher color graded stones appeared to be darker in hue than gems which, according to their grade, should have been whiter.  Some gems were deeper and some wider for the same carat weight.  Some gems had bigger or smaller tables - their assorted crown angles varied; there were different girdle thickness, and these stones ALL LOOKED DIFFERENT.

If I do a computer search through our primary wholesale diamond database, and search only stones which are between 2.00 and 2.05 carats in weight, all graded E in color and SI-2 in clarity, all graded Very Good Cut, and all GIA certified, the WHOLESALE price to me ranges from a low of $12,663 to a high of $21,420.  On paper these stones are all graded EXACTLY the same by the GIA.  It should be obvious to you that not all stones with equal grading are in fact equal in value, or equal in appearance.

As I began looking for a stone to meet your request I avoided searching for only the cheaper stones, as my 30 years of experience in the diamond business has convinced me that cheap stones are typically discounted for a good reason.  Instead of shopping for price, I concentrated on locating a stone for you that was a real GEM, with all of its quality ducks in a row.  After your side-by-side comparisons of several diamonds, the gem you selected from among those stones was a great stone, and extremely well priced. 

If you really want to buy the cheaper rock let me know.  However, I suspect you would feel more comfortable giving your fiancée a gem that was selected on quality, not on price.  Let me know what you want to do; I have your ring here, but can send it and the diamond back if you think a less expensive stone is the way for you to go.

Joe Thon,

Partner, NEGS

...
The Gem Guys
E-Mail NEGEMS Homepage NEGEMS

Rapaport Market Comment for January 13, 2012

International diamond markets show stable pricing, but trading remains cautious. Uncut diamond rough selling at slightly lower prices to dealers as cutters expect miners and distributors to reduce high asking prices from those of late last year. Solid Far East diamond demand ahead of Chinese New Year. Global jewelry retailers report steady Christmas sales, however with tight profits due to higher gold and gem costs.  Expect to see stable jewelry and gem  prices in the U.S. retail market due to strong foreign demand using a larger portion of the available goods.

 ...
The Gem Guys
E-Mail NEGEMS Homepage NEGEMS

Taylor auction final update

The Elizabeth Taylor jewelry auction set several significant records for this type of sales event.  Noteworthy milestones were the 24 items that sold for over $1 million, with six pieces going for more than $5 million each.

A major highlights of the sale included a 15 minute rapid bidding battle for the Burton wedding bands. These bands were given to Ms. Taylor by Richard Burton on their two marriages, first in 1964 and again in1975.  Pre-auction estimates were that the bands would bring fetch $6,000–8,000. The final price was $1,022,500. Not too shabby!!!!

...
The Gem Guys
E-Mail NEGEMS Homepage NEGEMS

Liz Taylor's Jewelry Auction

According to a just published Rapaport News article, early sales in Christie’s Auction Gallery sale of Elizabeth Taylor’s collection of jewels far exceeded their pre auction estimates.  The first part of the auction has achieved record prices at Christie’s, and they  reported that the first portion of the four-day sale generated $115.9 million in sales.  This makes it the most valuable jewelry auction in history. All of the 80 lots offered yesterday were sold. 

So far, the top lot sold was ''La Peregrina'' (pictured), a natural pearl, diamond, ruby and cultured pearl necklace by Cartier which went for $11.8 million, a price well above the high presale estimate of $3 million.  This piece set a record for a pearl jewel sold at auction.

Marc Porter, the chairman of Christie’s America’s, stated that the auction drew in bids from all over the world. In advance of the event Christie’s exhibited the collection in Hong Kong, Moscow, London, Tokyo, Los Angeles, Dubai, Geneva and Paris.

...
The Gem Guys
E-Mail NEGEMS Homepage NEGEMS