Wednesday, 5 April 2017

How diamonds form

Carbon on its own cannot form into diamonds even deep below the surface of the Earth. There are a few things that have to happen in just the right way. First of all the subsurface carbon is located about 150 km below the Earth's crust has to be subjected to immense heat and pressure. Coal and diamonds are both composed primarily of carbon. Their chemical structures have marked differences.
Coal is formed from highly impure carbon. This carbon generally contains  the following elements: oxygen, selenium, hydrogen, nitrogen and sulfur. Diamonds on the other hand require an absolutely pure source of carbon. If there is any defect in purity the diamond will generally change color or become too included to be worked by diamond jewelers.
When carbon sources which are very pure such as carbon dioxide are trapped deep under the Earth’s surface, conditions are ideal for the formation of diamonds. 725,000 PSI is about the level of pressure needed to compress the carbon into a diamond lattice with prefect 3-fold symmetry. this has to be coupled with high temperatures of about 1204˚C.
Only when these conditions are met can diamonds begin to form The carbon atoms begin to bond with four other carbon atoms. This creates the type of lattice which is the source of a diamond’s strength.
The diamond forming is only the first part of the process. All diamonds we get to access have been shuttled closer to the Earth's surface by geological movement.

How diamonds are brought to the surface

Diamonds are mined all over the world in areas that were brought to the surface through volcanic eruptions. Some of these eruptions are known to have been quite violent in nature. Scientists believe that the process of moving them from their formation location to the surface would have occurred very rapidly, in as little as a few hours. The force required to accomplish this would have been tremendous. It would have required volcanic eruptions traveling at roughly 30 miles per hour. The diamonds would then have been spewn out and strewn about the surface. The main reason scientists believe the process would have occurred with such speed is because if diamonds were subjected to the intense lava for extended periods of time, then they would have formed into graphite on the way up.
After volcanic eruptions brought the diamonds to the surface, they became contained in a material called Kimberlite. This is essentially cooled volcanic rock. When sealed inside of Kimberlite, they can maintain their natural hard and clear form. One aspect of diamond creation researchers struggle to understand is how long it takes for diamonds to form. Exact conditions of natural diamond formation are impossible to replicate in a lab, so the best determination method is carbon dating. Dating diamonds in this way give in an estimated age of between hundreds of millions to billions of years.

Thursday, 30 March 2017

Emerald Cut Diamonds

The emerald cut diamond is an oblong cut diamond with truncated corners.
Emerald cut diamonds are also referred to as "Cut-Cornered Rectangular Modified Brilliant."

It is an ideal shape for showing off the warmer tones of a stone. There are other shapes which are better suited for displaying elements such as sparkle, fire, and brilliance. The shape of emerald cut diamonds show off both the color and the clarity of a diamond. It is a little harder to to avoid seeing the inclusions in an emerald cut diamond so the higher clarity grades are more highly sought after when an emerald cut is purchased.

Ring settings which feature emerald cut diamonds as the main stone often include side stones. This is found to greatly enhance the center diamond. An interesting feature of emerald cut diamonds is that they look bigger for their carat weight than a great deal of other types of cuts.

People who want a big rock, and would rather have less sparkle than a traditional round cut brilliant often opt to buy an emerald cut diamond.

screenshot of news announcement on diamonds.net
Source: http://www.diamonds.net/News/NewsItem.aspx?ArticleID=58059


A blue diamond ring went under the hammer in Geneva in November 2016 with an estimated price tag of $15 million to $25 million, or up to $3.1 million per carat.

The square emerald-cut, 8.01-carat, fancy vivid blue diamond, named the ‘Sky Blue Diamond,’ headlined Sotheby’s Magnificent Jewels and Noble Jewels auction on November 16.

Fancy vivid blue, the highest color grade possible for a blue diamond, had at the time been awarded to no more than one percent of blue diamonds submitted to the Gemological Institute of America, Sotheby’s said. The fancy vivid blue diamond had been mounted by Cartier. The diamond is reported to have “excellent” polish and is a type-IIb stone.

The Sky Blue Diamond was the latest in a string of blue diamonds sold by leading auctioneers. Earlier that same year the 14.62-carat Oppenheimer Blue fetched a world-record $57.5 million at a Christie’s sale in Geneva in May.  Sotheby’s brought in $48.5 million for the Blue Moon of Josephine in the Swiss city November 2015.

Another emerald cut diamond auction was announced this month. 

source
At its Magnificent Jewels auction in Hong Kong this May, Christie’s unveiled the top lots that will go under the hammer including Harry Winston’s famous Jonker V diamond.
The rectangular-cut, 25.27-carat, D-color, VVS2-clarity diamond is expected to sell for no less than $2.2 million, though speculation about the final price is thought could reach up to $3.6 million. That is an incredible $142,461 per carat.

The stone is one of 13 polished diamonds cut from the famous 726-carat Jonker rough. The discovery was made by digger Jacob Jonker at South Africa’s Elandsfontein mine in 1934. The rough diamond at the time ranked as the world’s fourth-largest gem-quality diamond. Christie's informs us that the diamond was sold in 1935 to Harry Winston. The stone was subsequently displayed during the Silver Jubilee Celebrations of the Coronation of King George V and Queen Mary.

Christie’s Hong Kong auction on May 30 will also feature an emerald-and-diamond necklace created by designer Edmond Chin, estimated at $3.6 million to $5 million.


Friday, 14 June 2013

A little trick to finding even more value.

Every individual diamond is unique.

Every individual person is unique.

Diamonds are graded by individuals.

So it could easily be assumed that the same diamond, if graded by two different people, would receive two differing grades.

This can be the case, though some more widely recognized laboratories have a greater degree of consistency across the board than smaller laboratories.

In June 2013, the Rapaport Diamond Trading Network (RapNet)  got back the results from 10 diamonds graded by half a dozen different brands of diamond grading laboratories. The degree of variance between grading laboratories was not always extreme though one thing was clear: some laboratories are stricter. The GIA labs ranked as the ones demanding the highest quality for a diamond to receive a high grade. An article on RapNet's analysis was published here: http://www.diamonds.net/news/NewsItem.aspx?ArticleID=43417

There was a surprise, though, in that IGI labs were almost on par with GIA and ranked higher than labs in the EGL USA network. However HRD, fell below EGL USA, followed by EGL Hong Kong and EGL Israel.

As the name on a diamond's grading certificate will affect the pricing, RapNet calculated how pricing had factored into the mix based on the reputation of grading laboratories. The result was that IGI diamonds are suffering from an unwarranted besmirched image. According to this report, two diamonds with an equal grade from GIA and IGI should be seen as fairly equal.  Yet the IGI diamond will invariably be listed with a lower price than the GIA graded diamond with an identical grade.


The RapNet analysis concluded that it is inadvisable for a diamond shopper to simply get sold on a particular brand of certificate, but to buy the diamond, not the certificate. This would mean establishing a good line of communication with the jeweler and getting a clear understanding of the qualities of the stone.

My conclusion is that looking at diamonds with an IGI certificate could turn up some very nice bargains.

Here is one jeweler who does stock both GIA and IGI diamonds: Melrose Visit Melrose.com


Wednesday, 8 August 2012

The "Sparkliest" Diamond Shape


What shape diamond are you going to get for the engagement ring? Round? Square? Oval? Pear? Heart?

They're all so nice! It can be difficult to choose. You could be after a shape that is popular or maybe you want to try something a little different.
  
If you look at the statistics on a site like mega diamond seller Blue Nile you'll see that most people end up choosing round diamonds.

The reason that round shaped diamonds, (technically called round brilliants) are such good sellers is because they are known to be designed in such a clever way that a larger proportion of light bounces back through the top of the diamond giving it a superior sparkle. Because it is so cleverly engineered to make the light bounce and disperse so nicely it is possible to have a very sparkly stone even in lower clarity diamonds. So you can get away with choosing a "J" stone which has been cut into a round shape. As a result the "J" round diamonds are the best sellers.

If you do choose this option it would be important to get a stone whose grading report says it has an "Excellent" cut grade.  Actually I recommend to always go for  an "Excellent" cut grade. Excellent cut can also be referred to by some grading labs as an "Ideal Cut" .

 The "cut grade" is something separate from the "cut".  "Cut grade" would be mentioned on a grading report and this refers to how well the diamond is cut to achieve that perfect sparkle. Scientific ways to plan and predict light performance were introduced by The Gemological Institute of America in 2005 which helps jewelers create the best possible diamond.

It's always a challenging task for cutters to create an "Ideal" or "Excellent" cut as they are working not only with the hardest mineral on earth, but they have to work out the best way to accomplish this without losing too much of the diamond. After all, the bigger the diamond the rarer it is. Imagine being a diamond cutter and lopping off $20,000 from the stone in one stroke. I'm sure it's happened. Hopefully not too often.

I am constantly surprised at the high quality stones people are buying online. Most people going into the local jewelers are actually quite happy with a "Very Good" cut, and rarely go for the clear diamonds, or those whose grading report says are Very Lightly Included. When you look at the stones on a site like James Allen you'll see a highly magnified diamond. At a jewelers you don't get as good a look as you would at James Allen. Also most people when buying from the local mall jeweler don't bother to ask about the grading report.

This is how the online retailers have captured a huge slice of the market place: by giving people the chance to look at the diamond's grading report, as well as offering a large selection.

Which brings me back to the topic I started with. The selection of shapes available is also quite vast.

Technically the "shape" is referred to by diamond jewelers as the "Cut". But they'll understand it if you say "shape".

The round brilliant cut has become the standard diamond shape due to its excellent light performance. Every other shape is called a Fancy cut.

The round brilliant has been around since the 1700's, so other shapes certainly preceded it. Mentions of oval shaped diamonds occur in 1304, and pear shapes were known in the 1400's.

The round brilliant's current design is the accumulation of many centuries of work, contributed to by people like Henry Morse (of Boston) in the 1860's, and later a few slight enhancements were introduced by Marcel Tolkowsky in 1919.

Some diamond cutters have created their own improvements and sell these diamonds directly. This is called a Signature Cut, and one such diamond is made by Brian Gavin Diamonds. The way these diamonds look are pretty impressive and very dazzling. Diamonds are already quite hypnotic, but the ones Brian Gavin cuts are just unbelievable.

Monday, 6 August 2012

The Diamond Fluorescence Advantage


Fluorescence in diamonds is one of those things that can be confusing.

Does it make the diamond glow in the dark? How does fluorescence affect the brilliance of a diamond in regular light? And if so, how?

Fluorescent diamonds

To answer the first question, a fluorescent diamond may glow a little in the dark, but it will more likely glow under black light (UV light).

And to answer the second question there are a few points which might help cut through some of the confusion surrounding fluorescence.

There are two seemingly contradictory things about fluorescence.

1. Strong fluorescence can give the diamond a milky look.

2. Fluorescence does not always give the diamond a milky look.

How can both of these things be true?

Here's why: One in 50,000 diamonds with strong fluorescence will look milky, but even then it will only be in certain lighting.

As a result of this slight risk, jewelers don't try to push the fluorescent diamonds. They even discount them. Diamonds whose Grading Report says: "Strong Fluorescence" will be priced just below diamonds with other features which are exactly the same.

So, how we can use this information to get a better deal when shopping for a diamond?

After all, even at a jewelers we won't see the diamond in all different types of lighting (tube light, natural daylight, fire light, candle light) and won't know if it has any issues.

And if we are looking to buy a diamond online we certainly won't be able to see the diamond.

So here's the solution.

I recommend calling the diamond vendor and speaking to them directly. Ask them to look at the diamond you want and describe it to you. Any jeweler worth his salt will know a good diamond when he sees one. It's going to be hard for them to hide their enthusiasm when looking at a good stone. They've seen hundreds of diamonds and know which ones are going to be the "magical" ones.

You'll have an advantage by doing this as the majority of online shoppers don't bother to pick up the telephone, or even bother to click the call button on their smartphone.

And you'll stand a good chance of picking up a bargain by doing so.

Since it is only possible to judge how fluorescence affects the brilliance of a diamond by having eyes on the diamond most people stay away from the ones which show strong fluorescence when buying diamonds online.

The savings we get by buying a diamond which has strong fluorescence come with a risk of the diamond not looking as brilliant as one would wish. However as this is not the case with every single diamond which has a strong fluorescence some people are willing to take the risk. This is actually pretty smart because the risk is in fact extremely small. Some diamonds with strong fluorescence are actually very beautiful. The fluorescence makes some diamonds look fantastic when exposed to UV light, and they will look even brighter than their grading report suggests.

The last thing you can do to make sure you do not end up with a diamond which is not to your liking is to inspect it when you get it and return it if it does not suit you. Jewelers are used to this and are perfectly happy to exchange it for another diamond when this happens. If you're lucky you might even be given one without fluorescence at no extra charge. But don't hold your breath on that one. 

Still, I hope these few points will give you an idea of how to use diamond fluorescence to your advantage.

Here's a meticulous diamond jeweler, who is also an incredible diamond cutter, that checks fluorescent diamonds before buying them at wholesale and makes sure they are the sparkly variety and not negatively affected at all by diamond fluorescence. I've been pretty impressed by his world class workmanship too. As well as decent prices. Worth checking out when you get a chance.

Wednesday, 1 August 2012

Diamond Clarity and What it Means.


Clarity is an important characteristic of a diamond if it is to be used in jewelry, particularly in an engagement ring, and it is important to know the clarity of a diamond before you buy one. Understanding what clarity means will give you an idea of how it affects the look of a diamond. It is actually quite easy. 

We can divide this up into two categories:

1 Diamonds with visual inclusions and blemishes,

2 Diamonds that are ‘eye clean’ meaning that there are no inclusions or blemishes that can be seen with the naked eye.

From there, the clarity of a diamond is further broken down into subcategories.

Many people mistakenly think that diamond clarity refers to how clear it is. This isn’t so. Clarity actually refers to the internal and external imperfections of the diamond. The best diamonds, of course get a grade of FL or IF – Flawless or Internally Flawless – meaning that it is perfect. A grade of I-1, I-2 or I-3 means that the diamond has inclusions, with a grade of I-3 being the worst which online dealers are willing to carry. In local malls you may get even more included than that. Inclusions are tiny specks, possibly crystals that were "included" in the carbon when it was forming into a diamond. They aren't necessarily bad, but too many can prevent the diamond from looking as sparkly as it could and it's best if they aren't visible from the top, which is the most visible part of the diamond when it is set in a ring.

Other grades are VVS1 and VVS2, which means that the diamond is very, very slightly included; VS1 and VS2, meaning the diamond is very slightly included; SI-1 and SI-2, which means that the diamond is slightly included.

Tuesday, 31 July 2012

How the Price of a Diamond is Determined



Pricing many products for sale is generally quite easy. It goes something like this:

Determine the costs of manufacturing, then the costs involved to market that item, and then mark it up by 15 – 30% or whatever the market can sustain.
Simple, right? Well, pricing diamonds isn’t nearly that simple. Not at all. This is because there are so many additional factors that come into play when diamonds are priced.

Diamond prices are determined first by adding the cost of the rough diamond, the cost of cutting the diamond, and all other costs necessary to turn the rough diamond into a something suitable for use in jewelry. Depending on the importance of the diamond, an independent company may be called in to certify the grade of the diamond based on color, cut, clarity, and weight.

As every stage involves professionals who are paid for their work the diamond becomes more expensive each time it changes hands. When it finally reaches a retailer the price will as expected be raised still more. Before reaching the retailer, however, the diamond must travel from the mine, to the cutter and polisher, to the independent grading company, and then to the primary market. Once it has reached the primary market, it will be purchased by diamond dealers and wholesalers, and from there it will be sold to retailers.

As you can see, the earlier you can purchase a diamond in the process, the lower the cost of the diamond will be – but not the value. The value is based on what the diamond will sell for in the market place – through a retailer.

If you own a diamond, and you have no idea how much it is worth, you can have it appraised. Just be aware that the appraisal may not be accurate. You will be better off obtaining a certificate through GIA – Gemological Institute of America. With the information on this certificate, you can use a cutter’s guide to accurately determine what your diamond is worth.

There are also many diamond price calculators available. These can be found on the Internet, and many diamond dealers use these as well. You must realize, however, that before you can accurately price a diamond, without a Diamond Grade Report, you need to know quite a bit about diamonds, such as different cuts, clarity, color, and weight and how each of those aspects adds to the value of a diamond, or decreases the value of the diamond as the case may be. 

Again, you will be better off if you get a Diamond Grading Report on the diamond, and use that information to look up the price in one of the guides that the diamond cutting industry uses. This will give you the most accurate value of the diamond in your possession, or of the diamond you are considering purchasing.