April Birthstone - Diamond
inApril 4, 2008 - 6:42am
The Diamond, birthstone for April, has become one of the most popular and desired gemstones of modern times. But it has not always been so. While always desired, it has only been since the late 19th century that most people have even had the opportunity to acquire diamond jewelry.
It is possible the Bible and the writings of Pliny the Elder reference diamond. In early writings the stone described as “adamas” or “adamant” may actually be a diamond. These terms come from a Greek word meaning “I tame” or “I subdue,” and refer to the hardness of the stone. However, in some ancient writings the term describes colorless sapphire, or corundum, which is also a very hard material.
Diamond, however, is the hardest naturally occurring material. It is composed of nearly pure carbon. Minor trace elements will create color in the stone. Nitrogen is probably the most common trace element and creates stones with tints of yellow, brown, or orange. Possessing such hardness also meant that most early diamonds were not cut into fashioned gems, but used as rough crystals in their natural shapes. The Crown of St. Stephen, in the Hungarian Crown jewels, is probably one of the oldest existing pieces with diamonds. It dates to the late 11th century. It was probably the 14th century before diamond fashioning techniques were developed.
Diamonds are formed at great depths, under intense heat and pressure. Until the late 19th century, they were rare enough that only royalty and the extremely wealthy could own one. The discoveries of diamonds in South Africa in late 1866 or early 1867 led to rapid development of the diamond fields, and the jewelry world has not been the same since.
Today, the mines of Russia, Botswana, Congo, and Australia lead in total production, although not all may be gem quality diamonds. Some particular types and grades of diamonds are used in industrial applications. Canada has recently become a producer of diamonds, in a volume that is rapidly gaining on South Africa. There have been many recent controversies over diamond production. Many shoppers wish to avoid these conflict diamonds, and may do so, by buying a diamond from a non-conflict producer, such as Australia or Canada. Antique jewelry and secondary market pieces also prevent the use of your purchase money for causes of which you may not approve.
Being the hardest natural substance does not mean that a diamond is indestructible, as any owner of a chipped or damaged diamond will attest. Diamonds have a “directional softness,” of sorts, known as cleavage, and a diamond can be broken rather easily along these lines. Diamond cutters have actually used the property of cleavage in the first stages of fashioning a finished diamond from the rough material. After careful study, a cutter will scribe a groove on a rough diamond (with a diamond tipped-tool), insert a metal wedge, and tap the wedge with a mallet. If he has done this properly, a section of stone will neatly break off. If he has miscalculated, the cutter may destroy a valuable rough diamond.
A well-formed rough diamond crystal often resembles two 4-sided pyramids, attached at the base. Early fashioned diamonds often bear a similarity to this shape, with just the top point of the pyramid being ground off, using another diamond as the grinder. The corners can also be rounded off using this method. This was normally done by hand until well into the 19th century, and the process is known as “bruting.”
Many diamonds cut before the development of mechanized bruting exhibit a squarish profile of their diameter because of this, including Old Mine Cuts. Older cutting styles like this and the Rose Cut, may indicate an older piece, but remember that a modern cutter may still produce these shapes.
Using diamonds as a polishing medium to create the individual faces, or facets, on diamonds occurred as early as the 14th century, probably originating in Venice. The diamond cutting industry developed there and spread to Flanders, Paris, and Antwerp. History credits Vincenzo Peruzzi, a Venetian, with the invention of the multi-faceted brilliant cut, around 1700. His cutting style had a distinctly square outline and 57-58 facets, and the Old Mine Cut style is very similar in style to his cut.
Most variations of the brilliant cut used in the 18th and 19th centuries preserved as much weight as possible, but lack in brilliance by modern standards. If one compares the depth of these stones to the diameter, one will notice they are much thicker than modern stones. Much of this extra weight is in the top portion of the stone – the crown, and the stones were undoubtedly dazzling under candlelight and gaslights of the time. The Old European Cut is a modification of the Old Mine Cut, with a circular outline, and the term should not be confused with European Cut, which describes something different.
Some cutters of the 19th century, such as Jefferies and Morse, cut round stones that resembled modern round brilliant diamonds, and some in the diamond trade considered them fools for wasting so much of the diamond. The development of modern and mechanized cutting processes made the newer cutting style practical. It was not until Marcel Tolkowsky studied the issue, around the time of World War I, that the diamond cutting industry conceded the shallow stones were more brilliant.
As we mentioned before, take care not to confuse the terms Old European Cut and European Cut. Frequently, the term European Cut applied indiscriminately and incorrectly used. It actually should only be used to describe stones cut to the proportions developed by W. F. Eppler, which feature a slightly shallower crown and crown angle, and a slightly deeper pavilion, than the proportions devised by Tolkowsky. The term European Cut should only be used by individuals experienced in diamond proportion grading, as the features are extremely difficult to measure or estimate, especially on a mounted stone.
Please remember that a skilled jeweler can replace a missing stone with another, and you may find a modern stone in an old piece or a family heirloom diamond in a newly created setting. To date the piece correctly, use the date of the most recent component, although a dealer may certainly mention that the piece is a hybrid, created with two components from different eras.
Diamonds are valued based on the 4 C’s: carat, clarity, color, and cut.
Carat is the weight of the stone. The greater the weight, the greater the value per carat, with a one carat stone selling for more than 2 half-carat stones of comparable quality. Easily obtained by weighing a loose stone, the weight can be estimated by measuring the depth and diameter of a stone in a mounting. When arriving at this kind of weight, a seller should always describe the weight as estimated and approximate. A one-carat diamond weighs 200 milligrams, or 1/5 of a gram. 1/100th of a carat is often referred to as a “point.” However, diamond weight is described using decimal equivalents, not points.
You may read more about this at http://www.ftc.gov/bcp/guides/jewel-gd.shtm .
Clarity grades indicate the presence or absence of natural inclusions in a diamond and should only be assigned to a diamond by someone with training in diamond grading. Diamonds, which are set in jewelry, may be graded, but sellers should disclose the stone was graded while in a setting. Some lower clarity grades may affect the brilliance and durability of a diamond, and the fewer natural inclusions, the higher the diamond value.
Color grades indicate the presence or absence of any tint of color in a stone. This can only be done with any degree of accuracy on an unset diamond, viewed from the back or through the body of the stone, in comparison to a diamond or diamonds of known color grades. Any color grade assigned to a mounted stone is only an approximation, and it should be disclosed the stone was graded while in a setting. The type of lighting used and any natural fluorescence in a diamond may also affect the perception of color in a stone. Someone trained in diamond grading should only assign color grades to a diamond. The absence of any noticeable color creates greater value in a diamond, with the exception of some intense “fancy” colors.
Black diamonds do occur in nature. The term may refer to diamonds fashioned from Carbonado, an aggregate form of diamond and is sometimes improperly used, to refer to diamonds with a large number of dark inclusions, which may cause the stone to have a blackish appearance, or to stones that have a grey body color. The term should not be used to refer to a rhinestone or other material, unless the true nature and composition of this material is clearly revealed in immediate proximity to the phrase “Black Diamond.” If it is glass, you must clearly state so in your title and description.
Cut may refer to two different things, the proportions a diamond is cut to, and the shape a diamond is cut to. Both may affect value. Only a professional, someone trained in diamond grading should conduct an analysis of the proportions of a diamond. Well-proportioned diamonds will bring a premium price compared to poorly cut stones, and certain proportions may create a diamond prone to damage when worn.
Round brilliant diamonds are traditionally the most popular shape. Sometimes another shape will become popular and demand a premium price for a time, but rounds are consistently the most desired shape. The oval, pear, marquise, and heart shapes are the traditional variations of the brilliant cutting style used on round stones. The emerald cut and baguette cuts are variations on the step cut. The Cushion Cut is an old timer, which has seen a recent revival, and may indicate an old stone, or a very new one. Square and rectangular modified brilliant cuts, such as the Princess Cut and Radiant Cut are new innovations, and will not be seen in antique and vintage pieces. The Asscher Cut, developed in the 1900’s, is a specific type of step-cut diamond. The Asscher Cut recently experienced a rival in popularity, so pieces featuring these stones are at opposite ends of a century-long span of time.
Fancy colors are in an area that falls outside of the traditional 4-Cs assessment of value. Diamonds that show a body color of blue, green, pink, red, purple, or orange are considered to have Fancy color. Diamonds with a distinct yellow, brown or grey color may also qualify for this term. These colors may occur naturally, or through irradiation treatment, a treatment developed in the early 20th century. The color in some early green treated diamonds is created by immersion in radium salts, creating stones with dangerous levels of radioactivity. Diamonds treated by other modern methods are safe. Natural Fancy Color diamonds may bring a large premium in price. The Hancock Red, a .95 carat round diamond with a natural purplish red color sold for $880, 000 in 1987, setting a world record for price per carat for a diamond, at $926,000 per carat.
A new world record for the per carat price of a diamond has been established, and a 6.04 carat vivid blue emerald cut stone is responsible. The Internally Flawless piece sold for $7,980,000 on October 8, 2007, putting the price per carat at around $1.3 million. It was acquired by Moussaieff Jewellers of London. Moussaieff also owns the largest natural
There were experiments in the late 19th century aimed at producing true synthetic diamond, which may have been successful, but this is unverified. General Electric produced true synthetic diamond in the 1950’s and many have worked on developing the process since then, with more success in the Fancy colored diamond area than in colorless diamonds. At least four companies are producing synthetics now, but only one of these firms produces anything other than Fancy colors.
Materials such as Cubic Zirconia and Moissanite are properly sold as diamond simulants, as are many other materials. These stones should not be represented as Synthetic Diamonds or as Man-Made Diamonds.
When a seller is using a third person document, such as an appraisal, in selling a piece of diamond jewelry, the appraisal needs to be quoted accurately, and the appraiser’s credentials should be mentioned. While a jeweler may possess certification from an educational organization, such as the Gemological Institute of America, this does not make their appraisal a “GIA Appraisal.” The GIA does not engage in appraisals, but does issue “Diamond Grading Reports.” Reports from a gemological laboratory and reports or appraisals by individuals trained by those institutions are not the same thing, and the descriptions of such written material are not interchangeable and should be presented in a way which causes no confusion. Many appraisals are issued with disclaimers and special notes, information which may need to be disclosed to buyers. A seller should consider placing a legible illustration of any appraisal documents in their listings, blocking out any personal information, such as a previous owner’s name.