Diamonds – Page 69

Type of ice found trapped in a diamond new to science

Ice VII inclusions found within diamonds is evidence for aqueous fluid in deep in Earth’s mantle.

The inclusions a high pressure form of water called ice VII present in diamonds sourced from between 410 and 660 km depth, the part of the mantle known as the transition zone.

The transition zone is a region where the stable minerals have high water storage capacity.

The inclusions suggest that local aqueous pockets form at the transition zone boundary owing to the release of chemically bound water as rock cycles in and out of this region.

Ice VII is about one and a half times more dense than regular ice but unlike the other phases of ice ice VII remains fairly stable even as the pressure increases.

Historic 910 carat, The Fifth Largest Diamond Recovered

Gem Diamonds has recovered a 910 carat rough diamond at its Letšeng mine in Lesotho, the fifth largest rough ever found.

The D colour type IIa diamond is the largest to be unearthed at Letšeng, outranking the 603 carat Lesotho Promise recovered in 2006.

That stone was sold for $12.4 million, to Graff Diamonds, which owns a 15% stake in Gem Diamonds.

Last year, Graff bought the 1,109 carat Lesedi la Rona, the second largest rough diamond in history, for $53 million, or $47,790 per carat.

The discovery follows a recent revival of exceptionally large stones recovered at Letšeng, which is known for its high value production.

Rough Trade Cautious at $455M De Beers Sale

Dealers reported a difficult but stable rough market as De Beers’ November sight closed with a value of $455 million — 4% lower than the same period a year ago.

The rough market improved slightly from the October sight, which was the smallest sale of the year as Indian manufacturing slowed for Diwali. However, sightholders still noted weak profitability on De Beers goods during November, with premiums on the secondary market close to zero.

Most boxes of diamonds from last week’s sight commanded prices on the dealer market that did not cover the costs of doing deals, explained Dudu Harari of diamond broker Bluedax in a report on the sight.

Petra Diamonds shares drop

More trouble for diamond miner Petra Diamonds yesterday after it warned it is heading into financial trouble with its lenders.

Petra has borrowed heavily to expand its operations in the country. The company is now likely to breach its banking covenants at the end of the year, because of the row with the government in Tanzania. As well as strikes at three of its mines in South Africa.

Petra diamonds is known for the size and quality of the diamonds produced at the famous Cullinan mine outside of Pretoria in South Africa.

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Classic car prices drop but diamonds and wine shine

Old Master paintings and classic cars have lost the luster, But the uber rich have seen their jewellery, fine wine and musical instruments jump in value again.

This according to to the Blue blooded UK bank Coutts’ passion index of the finest things. Now in its twelfth year.

Thanks to 16.4 percent rises in instrument, 11.6 percent in jewelry prices and a near 10 percent jump in wines. Also a rise in watch prices of 6.7 percent.

One of the biggest jumps is for coins where gains since 2005 hit 225 percent.

Ferrari, Aston Martin, Jaguar ,Porsche and other collectable Classic cars whose prices have risen more than 332 percent since 2005, also went into decline.

Prices for fine art dropped between 4.3 and 7.9 percent last year. Post the financial crisis the Old Masters and 19th Century Art has been the worst performers. Down by more than 40 percent on a cost adjusted return basis.

Diamond Futures Exchange Launches In India

To help the Diamond industry limit losses when polished prices fluctuate. The Indian Commodity Exchange has launched the first diamond futures trading contract.

Diamond futures contracts work as price insurance, when fluctuations impact the value of inventories. With the futures trading traders agree on a price for a contract.

The new exchange platform gives investors a format similar to commodities exchanges such as Comex, Nymex and the London Metal Exchange.

Over 100 members and approximately 4,000 clients have registered with ICEX exchange.

The Indian government approved diamond futures trading in September 2016.

De Beers Raises Marketing Budget to USD $140M

De Beers marketing spend this years is more than $140 million, This is the biggest De Beers push in a decade.

The marketing will focus on increasing consumer demand for diamond jewellery in US, China and Indian markets.

The De Beers brands, Forevermark and De Beers Diamond Jewellers. Will receive the most funding, But Debeers will also increase its contributions to the Diamond Producers Association and India’s Gem & Jewellery Export Promotion Council.

Stephen Lussier, De Beers’ executive vice president of marketing and CEO of Forevermark. Said the consumer expenditure for diamond jewellery over the past five years collectively has been the highest on record. and this made the outlook positive.

July, 2017February, 2025

Upper-Girdle Facet

An Upper-Girdle Facet refers to a triangle-shaped facet that is positioned along the girdle of a diamond, specifically on the crown portion. These facets are part of the overall diamond structure and play a role in both the aesthetic appeal and the light performance of the diamond. They are located just above the girdle (the widest part of the diamond), and they help to define the outline and symmetry of the diamond.

Key Characteristics of Upper-Girdle Facets
Location:

The upper-girdle facets are found on the crown of the diamond, which is the top portion above the girdle. The facets extend from the girdle towards the top of the diamond, near the table facet.
These facets are positioned between the star facets (which surround the table) and the bezel facets (which form the uppermost portion of the crown, adjacent to the girdle).
Shape:

The upper-girdle facets are typically triangle-shaped, although their exact shape can vary slightly depending on the cut of the diamond.
The facet shape is designed to complement the overall geometry of the diamond and align symmetrically with the other facets to ensure optimal light reflection and brilliance.
Function and Impact:

Upper-girdle facets play an important role in the light performance of a diamond. They help to create the overall brilliance and scintillation (the flashes of light) seen when the diamond is moved.
These facets aid in directing light into the diamond and back out through the top, contributing to the sparkle and life that diamonds are known for. The way these facets are cut affects how well light enters the diamond, as well as how it is reflected and dispersed, enhancing the fire and brilliance.
Proportions and Symmetry:

Upper-girdle facets are often assessed in terms of proportions and symmetry during diamond grading. When properly aligned and proportioned, they contribute positively to the overall visual appeal of the diamond.
These facets need to be carefully crafted to ensure that they work in harmony with the other facets, such as the table, bezel facets, and pavilion facets, to produce the maximum amount of light reflection and refraction.
Importance in Diamond Cut:

Upper-girdle facets are part of the overall cut quality of the diamond, which is one of the most important factors in determining its value and visual appeal.
The quality of the cut—including how the upper-girdle facets are shaped, sized, and aligned—directly affects the diamond’s brilliance and scintillation. Therefore, these facets are essential in achieving an excellent cut grade on a diamond grading report.
Role in Different Cuts
In the most popular diamond shape, the round brilliant cut, the upper-girdle facets are specifically designed to enhance the diamond’s ability to reflect light and produce the desired sparkle.
In fancy-shaped diamonds, such as emerald cut or pear-shaped diamonds, the use of upper-girdle facets may vary or be absent, as different cutting styles have different faceting structures tailored to the shape and proportions of the diamond.
Visual and Aesthetic Impact
Properly cut upper-girdle facets contribute to the diamond’s symmetry and overall visual appeal. When these facets are aligned and proportioned correctly, they create a diamond that has a balanced, harmonious appearance.
These facets can also affect the appearance of the diamond’s size, as they help to define the outer edges of the diamond, creating the appearance of a larger, more well-defined shape.

The upper-girdle facets of a diamond are important, triangular facets positioned on the crown just above the girdle. These facets play a significant role in the diamond’s light performance, contributing to its brilliance, fire, and overall aesthetic appeal. The alignment and proportion of upper-girdle facets are crucial for ensuring a well-cut diamond that exhibits maximum sparkle. Their position and shape help to enhance the overall symmetry and light reflection, making them an essential element in the overall cut quality and beauty of the diamond.

July, 2017February, 2025

Wavy Girdle

A wavy girdle refers to a girdle of a diamond that is uneven in thickness or does not maintain a consistent, smooth plane all the way around the diamond’s circumference. This type of girdle is irregular, and rather than being perfectly straight and uniform, it undulates, creating a wave-like pattern along the edge of the diamond.

Key Characteristics of a Wavy Girdle
Uneven Thickness:

In a wavy girdle, the thickness of the girdle is not uniform. Some sections may be slightly thicker, while others are thinner. This unevenness in thickness can create a noticeable waviness around the diamond’s edge.
The girdle is the outermost edge of the diamond, and its thickness is important in protecting the stone from chips and fractures. A wavy girdle may make the diamond more prone to damage in certain areas due to its inconsistency.
Shape and Appearance:

A wavy girdle does not follow a straight, flat plane around the diamond. Instead, it may have a more undulating, curving, or irregular appearance. This undulation can result from imperfections in the rough diamond or the cutting process.
The effect is not always visible to the naked eye but can be detected under magnification or with careful inspection, especially if the waves are pronounced.
Effect on Symmetry:

The symmetry of a diamond is a critical aspect of its overall cut grade. A wavy girdle negatively impacts the symmetry of the diamond, as it deviates from the ideal, uniform shape that is expected from a well-cut diamond.
Since symmetry is a significant factor in the visual appeal of a diamond, a wavy girdle can detract from the diamond’s overall aesthetic and brilliance. It may cause slight misalignment in the overall shape of the diamond, making it appear less polished or balanced.
Impact on Diamond Grading:

When grading a diamond, the symmetry and girdle quality are evaluated. A wavy girdle will typically result in a lower symmetry grade. The grading report will often reflect this flaw, which can affect the overall value of the diamond.
A diamond with a wavy girdle may receive a grade that indicates some loss of symmetry, which can influence its desirability for certain buyers.
Causes of a Wavy Girdle:

A wavy girdle can result from the natural formation of the diamond in the earth or from imperfections in the cutting process. When the diamond is being cut, a lack of precision or inconsistency in the cutting machinery can lead to uneven girdle contours.
The shape of the original rough diamond may also play a role in the creation of a wavy girdle. In some cases, rough diamonds may have natural cracks, inclusions, or irregularities that cause the girdle to be cut unevenly.
Potential for Damage:

While the girdle is designed to protect the diamond from damage, a wavy girdle can sometimes create weak points or areas that are more vulnerable to chipping or cracking. Since the thickness varies along the edge, certain areas of the girdle may be thinner, making those points more prone to injury.
Aesthetic Impact:

Although a wavy girdle may not be immediately noticeable, it can impact the overall shape of the diamond, especially in certain cuts. For instance, in round brilliant or princess cuts, where symmetry is key, a wavy girdle may disrupt the round or square shape, creating an unbalanced or slightly skewed appearance.
For diamonds with specific shapes, such as emerald or pear-shaped, a wavy girdle can alter the uniformity of the outline, which may detract from the symmetry and elegance of the stone.

A wavy girdle is an irregularity in the girdle of a diamond, where the thickness varies or the edge does not follow a consistent plane. This can result from natural imperfections in the rough diamond or the cutting process and can negatively affect the symmetry and overall appearance of the diamond. A wavy girdle typically leads to a lower symmetry grade during the grading process, which in turn may impact the diamond’s value and desirability. Although it may not be immediately visible, a wavy girdle can influence the aesthetic balance and light performance of the diamond, making it an important factor to consider in a diamond’s evaluation.