Precious Stones Information

Extraterrestrial formation

Tue, 30 Mar 2010 07:11:00 +0000

Not all diamonds that are found on Earth originated here. A type of diamond called carbonado that is found in South America and Africa may have been deposited there via an asteroid impact (not formed from the impact) over 3 billion years ago. These diamonds may have formed in the intrastellar environment, but as of 2008, there was no scientific consensus on how carbonado diamonds formed.

Presolar grains in many meteorites found on Earth contain nanodiamonds of extraterrestrial origination, probably formed in supernovas. Scientific evidence shows that white dwarf stars have a core of crystallized carbon and oxygen nuclei. The largest of these found in the whole universe so far, BPM 37093, is located 50 light-years (4.7×1014 km) away in the constellation Centaurus. A news release from the Harvard-Smithsonian Center for Astrophysics described that the 2,500-mile (4,000 km)-wide stellar core as a diamond.

Thermal stability of Diamonds

Tue, 09 Mar 2010 05:23:00 +0000

Diamond and graphite are two different allotropes of carbon: pure forms of the same element that differ in structure.

Being a form of carbon, diamond oxidizes in air if it is heated over 700 °C. In the absence of oxygen, for e.g. in a flow of high-purity argon gas, diamond can be heated up to about 1700 °C. Its surface blackens, yet it can be recovered by re-polishing. At high pressure diamond can be heated up to 2500 °C, and a report published in 2009 suggests that diamond can withstand temperatures of 3000 °C and above.

Diamonds are carbon crystals that usually form deep within the Earth under high temperatures and extreme pressures. At surface air pressure, diamonds are not as stable as graphite, and so the decay of diamond is thermodynamically favorable (δH = −2 kJ / mol). So, contrary to De Beers' ad campaign extending from 1948 to at least 2006 under the slogan "A diamond is forever”, diamonds are certainly not forever. However, owing to a very large kinetic energy barrier, diamonds are generally metastable; they will not decay into graphite under normal conditions.

Synthetic and Artificial Gemstones

Sat, 27 Feb 2010 06:28:00 +0000

However, Gemstones created in lab are not imitations. For example, diamonds, ruby, sapphires and emeralds have been manufactured in labs to possess identical chemical and physical characteristics as with the naturally occurring variety. Synthetic corundums, including ruby and sapphire, are very common and they cost only comparatively lesser than the natural stones. Smaller synthetic diamonds are manufactured in large quantities as industrial abrasives. In addition larger synthetic diamonds of gemstone quality, especially of the colored variety, are also manufactured.

Some gemstones are manufactured in order to imitate other gemstones. As an example, cubic zirconia is a synthetic diamond simulant composed of zirconium oxide. Moissanite is another similar example. The imitations copy the look and color of the real ones but possess neither their chemical nor physical characteristics.

Whether a gemstone is a natural stone or a lab-created stone, the characteristics of each are similar. Lab-created stones usually tend to have a more vivid color to them, as impurities are not present in a lab, so therefore do not affect the clarity or color of the stone.

Heat treatment to Gemstones

Fri, 26 Feb 2010 06:30:00 +0000

Heat can improve gemstones color or clarity. The heating process has been well known to gem miners and cutters for centuries, and in many stone types heating is commonly practiced. Most citrine is made by treating amethyst with heat and partial heating with strong gradient results in ametrine - a stone partly amethyst and partly citrine. Much aquamarine is heat treated to remove yellow tones and to change the green color into the more desirable blue or enhance its existing blue color to a purer blue. Nearly all tanzanite is heated at low temperatures to remove brown undertones and give a more suitable blue/purple color. A considerable portion of all sapphire and ruby is treated with various heat treatments to improve both color and clarity.

When jewelry containing diamonds is heated the diamond should be protected with boracic acid; else the diamond could be burned on the surface or even burned completely up. When jewelry containing sapphires or rubies is heated up, it should not be coated with boracic acid or any other substance, as this can etch the surface; it does not have to be "protected" like a diamond.

Industrial uses of Diamond

Tue, 23 Feb 2010 10:13:00 +0000

The market for industrial-grade diamonds operates very much differently from its gem-grade counterpart. Industrial diamonds are mostly valued for their hardness and heat conductivity, making many of the gemological characteristics of diamonds, such as clarity and color, irrelevant for most applications. This helps explain why 80% of mined diamonds are unsuitable for use as gemstones, are destined for industrial use. In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s; another 570 million carats (114 tons) of synthetic diamond is produced annually for the industrial purpose. Approximately 90% of diamond grinding grit is basically of synthetic origin.

The boundary between gem-quality diamonds and industrial diamonds is partly defined and partly depends on market conditions. Within the category of industrial diamonds, there is a sub-category comprising the lowest-quality, mostly opaque stones, which are called as bort.

Industrial use of diamonds has been historically associated with their hardness; this property makes diamond the ideal material for cutting and grinding tools. As the hardest known naturally occurring material, diamond can be used to polish, cut, or wear away any material, including the other diamonds. Common industrial adaptations of this typical ability include diamond-tipped drill bits and saws, and the use of diamond powder as an abrasive. Less expensive industrial-grade diamonds, known as bort, with more flaws and poorer color than other gems, are used for such purposes. Diamond is not suitable for machining ferrous alloys at high speeds, as carbon is soluble in iron at the higher temperatures created by high-speed machining, leading to largely increased wear on diamond tools when compared to other alternatives.

Specialized applications involve use in laboratories as containment for high pressure experiments, high-performance bearings, and limited use in specialized windows. With the continuing advances being made in the production of synthetic diamonds, future applications have become feasible. Garnering much excitement is the main use of diamond as a semiconductor suitable to build microchips, or the use of diamond as a heat sink in electronics.

Diamond Clarity

Tue, 23 Feb 2010 05:11:00 +0000

Diamond clarity is a quality of diamonds related to the existence and visual appearance of internal characteristics of a diamond called inclusions, and surface defects called blemishes. Clarity is the important one of the four Cs of diamond grading, the others being carat, color, and cut. Inclusions may either be crystals of a foreign material or another diamond crystal, or structural imperfections such as tiny cracks that can appear whitish or cloudy. Factors such as the number, size, color, relative location, orientation, and visibility of inclusions can affect the relative clarity of a diamond. A clarity grade is assigned based on the overall appearance of the stone less than 10x magnification.

Most inclusions that are present in gem-quality diamonds don’t affect the diamonds' performance or structural integrity. However, large clouds can in turn affect a diamond's ability to transmit and scatter light. Large cracks that are close to or breaking the surface may reduce a diamond's resistance to fracture.

Usually diamonds with higher clarity grades are more valued, with the exceedingly rare "flawless" graded diamond fetching the highest price. Minor inclusions or blemishes are useful, as they can also be used as unique identifying marks analogous to fingerprints. In addition, as synthetic diamond technology improves and distinguishing between natural and synthetic diamonds becomes very difficult, inclusions or blemishes can be used as proof of natural origin.

Diamond formation

Mon, 22 Feb 2010 04:49:00 +0000

Diamonds form between 120-200 kms or 75-120 miles deep in the earth's surface. According to geologists the first delivery of diamonds was somewhere around 2.5 billion years ago and the latest was 45 million years ago. According to science, the carbon that makes diamonds comes from the melting of pre-existing rocks in the Earth's upper surface mantle. There is an abundant quantity of carbon atoms in the mantle.

Temperature changes in the upper mantle forces the carbon atoms to go deeper and it melts and finally becomes new rock, when the temperature reduces. If other conditions like pressure and chemistry works right then the carbon atoms in the melting crustal rock bond to build diamond crystals. Yet there is no guarantee that these carbon atoms will surely turn into diamonds. Either if the temperature rises or the pressure drops then the diamond crystals may melt partially or totally dissolve. Even if they do form, it would take thousands of years for those diamonds to come anywhere near the surface.

Color Factors

Fri, 19 Feb 2010 08:43:00 +0000

Color is the most impressive and attractive feature of gemstones. The color of any material is the result of the nature of light itself. Daylight, often termed as white light, is actually a mixture of different colors of light. When light passes through a material, some of them may be absorbed, while the rest passes through. The part which is not absorbed reaches the eye as white light minus the absorbed colors. A ruby appears red because it absorbs all the other colors of white light - blue, yellow, green, etc. – other than red.

The same material can exhibit various different colors. For example ruby and sapphire have the same chemical composition, but they exhibit different colors. Though the same gemstone can occur in many different colors: sapphires show different shades of blue and pink and "fancy sapphires" exhibit a whole range of other colors from yellow to orange-pink, the latter called "Padparadscha sapphire".

This difference in color depends on the atomic structure of the stone. Although the different stones have the same chemical composition formally, they are not exactly the same. Every now and then an atom is completely replaced by a totally different atom. These so called impurities are enough to absorb certain colors and leave the other colors unaffected.

For an example: beryl, which is colorless in its pure mineral form, becomes emerald with chromium impurities. If you add manganese instead of chromium, it becomes pink morganite. Added with iron, it becomes aquamarine. Some gemstone treatments make use of these facts thus changing the color of the gem.

Diamond enhancements

Thu, 18 Feb 2010 05:31:00 +0000

Diamond enhancements are certain peculiar treatments performed on natural or synthetic diamonds, usually those already cut and polished into a gem, which are designed to better the gemological characteristics of the stone in one or more ways.

These techniques generally include laser drilling to remove inclusions, application of sealants to fill cracks, treatments to improve a white diamond's color grade, and treatments to give fancy color to a white diamond.

In addition, coatings are increasingly used to give a diamond simulant such as cubic zirconia a more "diamond-like" appearance. One such substance is carbon-an amorphous carbonaceous material, which looks like a diamond that has some physical properties similar to those of the diamond. Advertising suggests that such kind of coating would transfer some of these diamond-like properties to the coated stone, hence enhancing the diamond simulant. Techniques such as Raman spectroscopy should easily identify such type of treatment.

Diamond Identification

Tue, 16 Feb 2010 05:41:00 +0000

Early diamond identification tests included a scratch test which relied completely on the superior hardness of diamond. Yet this test is destructive, as a diamond can scratch diamond, and is rarely used nowadays. Instead, Diamond identification can also rely on its superior thermal conductivity. Electronic thermal probes are commonly used in the gemological centers to separate diamonds from their imitations. They consist of a pair of battery-powered thermistors mounted in a fine copper tip in which one functions as a heating device while the other measures the temperature of the copper tip: if the stone being tested is a diamond, it will conduct the tip's thermal energy rapidly enough to produce a measurable temperature drop. This test takes around 2–3 seconds.

Whereas the thermal probe can separate diamonds from most of their simulants, distinguishing between various types of diamond irradiated or non-irradiated, etc., requires more advanced, optical techniques. These techniques are also used for some diamonds simulants, such as silicon carbide, which pass the thermal conductivity test. Optical techniques can distinguish between natural diamonds and synthetic diamonds. "Perfect" crystals have never been found, so both natural and synthetic diamonds always possess characteristic imperfections, arising from the circumstances of their crystal growth, that allow them to be distinguished from each other.

Laboratories use techniques such as spectroscopy, microscopy and luminescence under shortwave ultraviolet light to find out a diamond's origin. They also include specially made machines to aid them in the identification process. Two screening machines are the Diamond Sure and the Diamond View, both are produced by the DTC and marketed by the GIA.

Several methods for identifying the synthetic diamonds can be performed, depending on the method of production and the color of the diamond. CVD diamonds can generally be determined by an orange fluorescence. D-J colored diamonds can usually be screened through the Swiss Gemological Institute’s Diamond Spotter. Similarly, natural diamonds usually have minor imperfections and flaws that are not seen in synthetic diamonds.

Exploration Diamond drilling

Fri, 12 Feb 2010 05:09:00 +0000

Exploration diamond drilling differs from other geological drilling where in that a solid core is extracted from depth, for examination on the surface. The key technology of the diamond drilling is the actual diamond bit itself. It is usually composed of industrial diamonds set into a soft metallic matrix. The diamonds are scattered all over the matrix, and the action relies on the matrix to slowly wear during the drilling, so as to expose more diamonds.
The bit is mounted onto a drill stem, which is in turn connected to a rotary drill. Water is injected into the drill pipe in order to wash out the rock cuttings produced by the bit. An actual diamond bit is a complex affair with many channels for washing.
The drill uses a diamond encrusted drill bit to drill through the rock. The drill produces a "core" that is photographed and split longitudinally. Half of the split core is kept under analysis while the other half is permanently stored for future use if necessary. A larger diameter core is the most preferred yet it is the most expensive. The commonly preferred diameter sizes of core are NQ and CHD 76.

Diamond simulants

Wed, 10 Feb 2010 04:49:00 +0000

A diamond simulant is generally a non-diamond material which is used to simulate the appearance of a diamond. Diamond-simulant gems are usually called as diamante. The most popular diamond simulant to most consumers is cubic zirconia.

The popular gemstone moissanite is quite often treated as a diamond simulant, although it is a gemstone in its own right. While moissanite seems similar to diamond, its main disadvantage as a diamond simulant is that cubic zirconia is much cheaper and arguably equally convincing. Generally both are produced synthetically.

Diamond cutting

Mon, 08 Feb 2010 11:21:00 +0000

The mined rough diamonds are usually converted into gems & jewelleries through a multi-step process called "cutting".

Diamonds are extremely hard, yet so brittle and can be easily split up by a single blow. The diamond cutting is traditionally considered as a delicate procedure requiring skills, scientific knowledge, tools and experience. Its final goal is to produce a faceted precious jewel where the specific angles between the facets would optimize the diamond luster that is dispersion of white light, whereas the number and area of facets would determine the weight of the final product.

The most time-consuming part of the cutting is the preliminary analysis of the raw stone. It needs to address several issues, bears much responsibility, and therefore can last years in case of unique diamonds. The following issues are considered:

The hardness of diamond and its ability to cleave strongly depend on the crystal orientation. Therefore, the crystallographic structure of the diamond to be cut is analyzed with the help of X-ray diffraction in order to choose the optimal cutting directions.

Most diamonds contain various visible non-diamond inclusions and crystal flaws. The cutter has to decide which flaws are to be removed by the cutting and which could be left undisturbed.

The diamond can be split by a single, well calculated blow of a hammer to a pointed tool, which is quick, yet risky. Alternatively, it can be cut using a diamond saw, which is a more reliable but tedious procedure.

Categories of diamond deposits

Tue, 02 Feb 2010 11:37:00 +0000

Naturally, there are two types of diamond deposits: primary and secondary deposits. Primary deposits are those in which the diamonds stay inside the original host rock (usually kimberlite) that expressed them to the surface. Secondary deposits are formed when the diamonds are battered from the host rock and concerted by the deed of water into alluvial deposits (in rivers) or marine deposits (in beaches).

In diamond searching, it is commonly accepted that economic primary diamond deposits are connected with ancient shields or "cratons". These cratons are large in size, coherent expanses of rock that have been physically stable for at least one billion years. Cratonic "keels" underneath these formations can expand to depths within the earth's layer wherever pressure and temperature conditions are favourable to diamond formation and preservation. The formation of these diamondiferous keels is composite which is one reason why kimberlites devoid of diamonds can occur in close proximity to luxuriantly diamondiferous ones.

China is the World's second largest diamond market

Thu, 28 Jan 2010 12:16:00 +0000

Currently China is the world's second biggest diamond market, subsequent to the United States and exceeding Japan, with government figures representing that import diamonds through the Shanghai Diamond Exchange increases 16.4 percent to more than $1.5 billion in 2009.

Japan imported $575.86 million value of polished diamonds in the first 11 months of 2009 whereas the United States imported $11.26 billion worth of polished in the same period.

"As the financial system continued to develop in a constant manner, consumer demand for jewelry continued to grow, particularly for diamonds for the wedding market".

China's economy produced 8.7 percent in 2009, according to the news agency. China's rapid growth positions at great difference to the shrinking economies of most Western countries during last year. Japan's diamond utilization has been steadily declining as the Japanese financial system continues to struggle and consumers state a shrinking appetite for diamond jewelry.

China has a growing middle class, a very huge population and a taste for Western luxury brands.

Local brides curiosity in diamond rings has been gradually growing in the past decade, after De Beers invested a great deal in marketing the trend to consumers. Initially popular in Beijing and Shanghai, the trend has extended to other major cities across China.

Synthetic and Artificial Gemstone Beads

Tue, 29 Dec 2009 06:37:00 +0000

Some of the stones are artificial to imitate other precious stones. For instance, cubic zirconia is a synthetic diamond stimulant composed of zirconium oxide. Imitations with a real stone in color, but do not have a real chemical or their physical uniqueness.

But, labs created gemstones are not imitations. For instance, ruby, sapphire and emeralds have been produced in laboratories, to have identical physical and chemical properties of natural varieties. Synthetic (lab created) corundums, including sapphire and ruby, and very often they are only a portion of the cost of natural stone. Smaller synthetic diamonds were produced in large quantity of industrial abrasives. Synthetic gem diamonds larger, high qualities, especially in varieties of color, are also produced.

This gemstone is natural stone or laboratory-created (synthetic) stone, uniqueness are the same for each. Laboratory-created stones are more vibrant colors to them, which pollutants are not present in the laboratory, so do not affect the clarity or color stone. Though, natural gemstones are still considered more valuable, on average, because of their relative rarity.

The source of the gemstones also does not affect its classification as a semi-precious and precious stones. Rubies, emeralds and sapphires are always gems, precious stones, as others are considered semi-precious.

Lesotho diamond could be biggest ever polished round diamond

Mon, 21 Dec 2009 12:34:00 +0000

A huge 478 carats diamond has been discovered in Lesotho's Letseng mine, mutually owned by Gem Diamonds and the Lesotho government.

According to specialists, it is previously the 20th largest rough diamond found, and if cut and polished, could be the largest ever polished round diamond, weighing in at 150 carats.

The well-known Koh-i-Noor diamond set in the British crown jewels is a 105 carat diamond.

But, the new diamond from Lesotho is still far smaller than the Cullinan diamond discovered in 1905, which was 3,106 carats uncut and yielded a teardrop shaped diamond of 530 carats called the Great Star of Africa.

Usually large diamonds are named, though none has been announced for the newly discovered stone.

Japan makes world's smallest diamond ring

Thu, 17 Dec 2009 07:10:00 +0000

Cheapskate husbands-to-be the world over have reason to celebrate today, after a Japanese company unveiled what is supposed to be the world's smallest diamond ring.

The ring has a 0.02 millimeter diameter and bears a five-billionth of a carat diamond. The ring can only be seen through a microscope.

Hitachi High-Technologies says it used technology usually used to produce semiconductors to make the ring.

It was created by Yasushi Kuroda, an employee of the company's subsidiary Hitachi Science Systems, to demonstrate that the company's equipment can be used to make micro-machines.

Kuroda took just two hours to make the ring using equipment with gallium ion beams which is usually used to inspect and manufacture semiconductor chips.

The ring was made from tungsten wire from light bulbs and the diamond, 0.01 millimeters in diameter, was from polishing powder, the officials said.

A digital microscope photo of the ring won the gold award at this year's Asia-Pacific Conference on Electron Microscopy.

Why the World's Largest Diamond is Special?

Mon, 14 Dec 2009 10:55:00 +0000

Diamonds are special for a number of reasons. Initially, diamonds are formed 90-100 miles below the Earth's crust. Secondly, diamonds take a billion years to form and work their way to the surface. Thirdly, diamonds are the hardest naturally-occurring substance. The world's largest diamond is extra special in that it also managed to remain whole and at a weight, size, and color than surpasses all other diamonds. The Greek derivative for diamond means unbeatable and the Golden Jubilee Diamond is an excellent example of the strength and durability of the diamond.

The top ten world's largest diamonds are as follows:

Golden Jubilee (545.67 carats)

Cullinan I (530.20 carats)

The Incomparable (407.48 carats)

Cullinan II (317.40 carats)

The Spirit of de Grisogono (312.24 carats)

The Centenary (273.85 carats)

The Jubilee (245.35 carats)

The De Beers (234.65 carats)

The Red Cross (205.07 carats)

The Millennium Star (203.04 carats)

Diamonds Are Forever Revealing New Insights Into Earth's Development

Wed, 09 Dec 2009 06:31:00 +0000

Researchers studied platinum group elements (PGE) inclusions in about 20 diamonds collected near the Bushveld Complex in South Africa. The complex is vast, measuring hundreds of kilometers in length, and it is one of the few places in the world where PGEs are found in large enough quantities to be mined. The Bushveld Complex is also very old-geologists put its age at just over 2 billion years-and formed by crystallization of the Bushveld magmas in a massive crustal magma chamber. The researchers looked at the PGEs in the diamonds, sometimes analyzing grains as small as a few micrograms. They found that the isotopic signatures of the PGEs in the diamonds and Bushveld ore minerals match, showing the main source of Bushveld platinum to be mantle, not crust falling into the magma chamber as previously thought.

Large Diamonds Made From Gas Are Hardest Yet

Fri, 04 Dec 2009 13:15:00 +0000

Arlington, Va.Producing a material that is harder than natural diamond has been a goal of materials science for decades. Now a group headed by scientists at the Carnegie Institution's Geophysical Laboratory in Washington, D.C., has produced gem-sized diamonds that are harder than any other crystals and at a rate up to 100 times faster than other methods used to date. The process opens up an entirely new way of producing diamond crystals for electronics, cutting tools and other industrial applications.

"This is a great example of fundamental research that will not only give us a better tool to duplicate conditions in the core of the Earth, but will stimulate many other scientific, technical and economic advances," said geologist James Whitcomb of the National Science Foundation (NSF)'s division of earth sciences, which funded the research.

"We believe these results are major breakthroughs in our field," said Chih-shiue Yan, lead author of the study published in the Feb. 20, online Physica Status Solidi. "Not only were the diamonds so hard they broke the measuring equipment, we were able to grow gem-sized crystals in about a day."

The researchers developed a special high-growth rate chemical vapor deposition (CVD) process to grow crystals. They then subjected the crystals to high-pressure, high-temperature treatment to further harden the material. In the CVD process, hydrogen gases and methane gases are bombarded with charged particles, or plasma, in a chamber. The plasma prompts a complex chemical reaction that results in a "carbon rain" that falls on a seed crystal in the chamber. Once on the seed, the carbon atoms arrange themselves in the same crystalline structure as the seed. This method has been used to grow diamond crystals up to 10 millimeters across and up to 4.5 millimeters thick.

CVD-produced crystals are very tough. "We noticed this when we tried to polish them into brilliant cuts," said Yan. "They were much harder to polish than conventional diamond crystals produced at high pressure and high temperature." The researchers then subjected the tough CVD crystals to high-temperature and high-pressure conditions. The diamonds were heated to 2000° C and put under pressures of 50,000 to 70,000 times atmospheric pressure for 10 minutes. This final process resulted in the ultra -hard material, which was at least 50 percent harder than conventional diamonds.

The research was also supported by the U.S. Department of Energy, the National Nuclear Security Agency, through the Carnegie/ DOE Alliances Center, and the W. M. Keck Foundation. It was conducted in collaboration with researchers at the Phoenix Crystal Corporation and Los Alamos National Laboratory.

Jwaneng Diamond Mine, Botswana

Tue, 01 Dec 2009 07:26:00 +0000

Botswana ranks first among the world's gem-quality diamond producers, and diamond mining makes up 70 percent of the nation's export revenue. The Jwaneng Diamond Mine, in south-central Botswana, sits atop the convergence of three kimberlite pipes-diamond-rich geologic formations. Because the pipes meet just below the surface and cover some 520,000 square meters (128.5 acres) at ground level, the diamonds are mined from an open pit rather than a mine tunneled below the surface.

The Enhanced Thematic Mapper Plus (ETM+) instrument on NASA's Landsat 7 satellite acquired this image of the Jwaneng Diamond Mine on May 17, 2001. The arid, flat landscape that fills most of this image appears in varying shades of brown, crisscrossed by pale beige roads. The Jwaneng Diamond Mine appears in the upper left quadrant of the picture, and a residential area appears near the bottom center.

At the center of the diamond mine, a series of concentric circles cut deeper and deeper into the ground. Surrounding the pit is a network of roads and structures related to the mining operation. Measured by the value of the diamonds recovered, the Jwaneng Diamond Mine is the world's richest, but the mine also produces 9.3 million metric tons of ore-diamond-bearing rock-and 37 million metric tons of waste rock every year. As open-pit mining operations carve farther below the ground surface, they often encounter water tables, and the sky-blue color at the center of the pit could result from water. Southwest of the mine, two large rectangular areas also appear to hold some water. These areas might be used to let fine sediment settle out of a watery solution.

The settlement southeast of the mine contrasts with the arid landscape as much as the mine does. Here, tiny dots of green hint at trees and grassy parks. The pale beige rectangles around the perimeter of this image are probably crops or fallow fields.

Rockwell Recovers Three Exceptional Fancy Stones From Saxendrift

Tue, 24 Nov 2009 12:35:00 +0000

Rockwell Diamonds recovered a salmon-pink, 30.54-carat stone and two intense fancy yellow stones of 35.54 carats and 36.32 carats at its Saxendrift alluvial diamond mine in October. The 30.54-carat, salmon-pink stone was a mix of pink, orange and brown, with the rough diamond's form described as flat, elongated and approximating a marquise shape. Rockwell described it as an excellent clean clarity, makeable stone that should yield a good recovery factor in the polished form, in spite of its flattened, elongated shape.

The 35.54-carat, intense fancy yellow stone was also of clean, excellent clarity. The shape has a "blocky" form that was previously octahedral, according to the Rockwell announcement, with all of its sides having been removed through the wear and abrasion that occurred during its extensive high-river transport. Three corners of the 36.32-carat, intense fancy yellow stone were broken, which left slight indentations; otherwise, it, too, was of excellent clean clarity and octahedral in shape.

These three stones are being processed through Rockwell's beneficiation agreement with Steinmetz Diamond Group in South Africa. Earlier this year, Rockwell recovered a 22.74-carat, intense yellow stone from Saxendrift, which Steinmetz cut and polished into an 8.88-carat, vivid yellow stone and sold this month.

Rockwell's president, John Bristow, said, "Our Saxendrift mine continues to yield an array of exceptional diamonds, including large stones and smaller, rare fancy stones of exceptional color. We expect the latest colored stones to attract strong rough prices in an improving market."

Source: http://www.diamonds.net/news/NewsItem.aspx?ArticleID=28597

white gold ruby rings

Fri, 06 Nov 2009 05:37:00 +0000

White gold ruby rings are the most popular items of jewelry that people buy the world over. Rings have been a part and parcel of many civilization and rituals the world over. This explains the craze for them, particularly white gold ruby rings.

Though they are a bit on the expensive side, people still don't mind spending for them since they make any occasion memorable. White gold ruby rings are loved possessions of the young and old alike.

White gold ruby rings appear to have caught the fancy of people around the world like never before. Almost everybody seems to be bewitched by the beauty of white gold ruby rings and wants one for them. Such is the craze for them in some places that the very word ring has become identical with them.

Sino Gold

Tue, 03 Nov 2009 12:08:00 +0000

Sino Gold has been active in China since 1996 and is China’s biggest foreign gold producer.

The Company is developing the Jinfeng gold mine in Guizhou Province, southern China, which has Mineral Resources contains 4.0 million ounces and Ore Reserves containing 2.9 million ounces.

Once developed, Jinfeng will be the next largest gold mine in China with production of 180,000 ounces per annum. A proposal to accelerate production from the underground mine as part of the Phase 2 expansion is at present being progressed.

The White Mountain project in Jilin Province, northeast China, has good potential to become Sino Gold's after that mine. Drilling during 2006 is aimed at increasing the Mineral Resource containing 436,000 ounces and succeeding the project to feasibility stage.
Sino Gold is a growth gold company that is dynamically pursuing a discovery and acquisition strategy in China. With a "first mover" advantage, it holds a strong spirited position in China.