32 posts categorized "Colored Gemstones"

Red Diamond For Sale

The Argyle Diamond Mine in Australia is famous for being the world’s premier source of pink colored diamonds but it is also the premier source of the few red colored diamonds known to exist.  To say that there is only a small number of true natural red colored diamonds is no exaggeration.  The number diamonds certified as red is estimated to be less than twenty so it is rare that a red diamond is seen in public, let alone available for sale.

Bruce Robinson Jewellers in Brisbane, Australia recently purchased a red diamond at the 2006 Argyle Pink Diamond Tender, which featured 65 exceptional colored diamonds.  While the purchase prices for the diamonds at the tender are confidential, the red diamond is now for sale and expected to demand a very high price.

The 0.54-carat brilliant-cut red diamond, named “The Lady in Red” measures only 5.13 mm and is I1 in clarity meaning it has inclusions visible to the unaided eye.  The diamond was a 1.46-carat rough diamond crystal and was cut and polished to its current 0.54-carat weight.  In spite of its small size, this diamond will probably be price well over $2 million.

Red diamonds are extremely rare.  The last red diamond sold for almost $1 million twenty years ago.  Because of their rarity and beauty, several red diamonds are among the most famous diamonds.

Moussaieff_red Perhaps the most famous of the red colored diamonds is the Moussaieff Red, a 5.11-carat ruby-red diamond making it the largest red colored diamond in the world.  Discovered by a farmer in Brazil in the 1990s, the internally flawless 13.90-carat rough crystal was cut by William Goldberg Diamond Corporation. The rare red stone was later sold to the Moussaieff Jewelers for a rumored $8 million.

The second largest red diamond is simply known as Red Diamond and is an emerald cut weighing 5.05 carats.  Its current location is unknown.

Another famous diamond is the De Young Red, a 5.03-carat round brilliant that is the third largest red diamond in the world.  The De Young Red is on display at the Smithsonian Museum in Washington, DC.  At one time it was mistakenly sold as a red garnet because the stone’s subtle brown hue give it an appearance more like a garnet than a rare red colored diamond.

The Hancock (Halphen) Red is an extraordinary deep ruby red making it exceptional among the reds even though it is smaller in carat weight at 0.95-carats.  In the 19th century, Edwin Streeter, a diamond dealer in Paris bought the extraordinary red known as the Halphen Red.  The stone disappeared from public view and was never seen again.  Almost a century later, a collector in England purchased a 0.95-carat red diamond, The Hancock Red, named after its owner Warren Hancock.  While there is no proof the two diamonds are in fact the same, the rarity of red diamonds makes it likely they are the same.  The purplish-red diamond sold for $880,000 ($926,000 per carat) at Christie’s in 1987.

Time will only tell what will happen to “The Lady in Red” that is currently for sale in Brisbane.


6.35 Carat Diamond Found in Arkansas

Rodendiamond635_carats2Donald and Brenda Roden of Point, Texas found a 6.35-carat coffee color, brown diamond at Crater of Diamonds State Park on September 23, 2006.  They named their gem the Roden Diamond and are uncertain at this time whether they will eventually sell or keep it.

Rodendiamond635_carats1Park Superintendent Tom Stolarz noted, “The Roden’s gem is the eighth largest find of the 25,714 diamonds discovered since the Crater of Diamonds became an Arkansas state park in 1972.”  He described the gem as “about he same size and color as a large coffee bean.  The gem has somewhat distorted octahedral shape and a metallic-looking shine that is characteristic of diamonds from the Crater of Diamonds.”

Crater of Diamonds State Park is one of 52 state parks administered by the State Parks Division of the Arkansas Department of Parks and Tourism and is located in southwest Arkansas two miles southeast of Murfreesboro.  The park is the world’s only publicly operated diamond site where the public is allowed to search and keep any gems found, regardless of value. 

Learn more about Crater of Diamonds State Park...


Magnificent Jewels at Christie's

Some of the most beautiful jewels in the world are sold at Christie’s New York and April 11 will be no exception.  Advertised as the Magnificent Jewels sale, this even will include the collection owned by Joan Kroc, the wife of McDonald’s founder, Ray Kroc.

Here are some of the fantastic gems and jewelry that will be auctioned in April.

Christiespear_1 Probably the most valuable item will be a magnificent loose pear-shaped diamond weighing 50.67 carats and graded D color and VVS2 clarity.  Estimated value is $2.25 to $2.50 million.

Christiesbluepear A truly unique colored diamond ring features a 14.43 carat pear-shaped fancy dark blue-gray diamond surrounded by pave set pink diamonds set in a platinum and 18 karat rose gold mounting.  Estimated value is $1.2 to $1.5 million.

Christiesnecklacepear One of the Joan Kroc items is a colored diamond necklace by Harry Winston that features a 42.13 carat pear shaped fancy intense yellow color diamond hanging from two row round diamond necklace.  Estimated value is $1.0 to $1.5 million.

Christiespearpave Pear shaped diamonds are the showcased shape and the sale includes a 12.02 carat pear shaped diamond with D color and Internally Flawless clarity set in a pave set diamond split shank platinum ring.  Estimated value is $600,000 to $800,000.

Christiesbluesapphirering An impressive cushion cut blue sapphire weighing 80.86 carats is set in a platinum mounting with bullet cut diamond side stones.  Estimated value is $350,000 to $500,000.

Christiesrectangularsapphire It is hard to find sapphires that have not been heat treated but the sale includes a 24.21 carat rectangular cut blue sapphire in a platinum mounting with pave set diamonds on the shank and prongs.  Estimated value is $350,000 to $500,000.

Christiesbutterfly A colored diamond and steel butterfly brooch, designed by Cartier, is sure to catch attention at the auction.  The wings have pave set fancy yellow diamonds enhanced with pear shaped white diamonds and oxidized steal veining.  The body is set with a carat pear shaped diamond, two cushion cut diamonds (2.68 and 6.33 carats) and pear shaped diamonds on the antennae.  Estimated value is $400,000 to $600,000.

Christiespinksquare A beautiful 5.25 carat modified square cut fancy pink diamond is set in a platinum and rose gold mounting flanked by trapeze cut white diamonds.  The center diamond is a natural fancy pink color with VVS2 clarity.  Estimated value is $400,000 to $600,000.

Christiesfeather_1 One of the more unique jewelry shapes at the sale will be a sapphire and diamond feather brooch designed by Flato.  The flexible, articulated feather has calibre cut sapphires extending from the stem with white pave set diamonds.  Estimated value is $30,000 to $40,000.

Discover more of the world’s most beautiful items at http://www.christies.com


Tanzanite

Tanzanite was enthusiastically celebrated after its discovery in 1967 as "Gemstone of the 20th Century.” The only known source of Tanzanite is a five square mile hilltop at Merelani, ten miles south of the Kilimanjaro International Airport in Tanzania.

While the correct name for the gemstone is “blue Zoisite,” the New York jewelry company, Tiffany, suggested it should be named after the place in occurs on the earth because the words “blue Zoisite" sounded unfortunately too much like the word "suicide". The name Tanzanite was used and has stuck helping this beautiful gemstone achieve success in the marketplace.

The deep blue colors of Tanzanite range from ultramarine to a light purplish blue. The most coveted color is a blue which shows a purplish hue. The source of its mesmerizing color is that tanzanite is trichroic: that is, it shows different colors when viewed in different directions. One direction is blue, another purple, and another bronze, adding subtle depths to the color.

Most rough crystals show a large proportion of the brownish-yellow, but the cutter may cure this by carefully heating the stone in an oven to about 500°C. This heating process requires careful attention because it is essential to determine the moment when the color turns blue. Heating is a treatment which is generally accepted in the trade and should be expected. Due to the heating, the most desirable rough stones are those that are relatively free of inclusions so that the heating process does not lead to fissures in the stone.

Tanzanite is a blue variety of the gemstone, Zoisite (hydrated calcium aluminum silicate) which has hardness 6.5 to 7 on the Mohr’s scale. It is not very scratch resistant so must be worn with care, especially in rings.

Tanzanites should be cleaned with warm, soapy water and a soft bristle brush. It should never be cleaned by ultrasonic method and because of its chemical composition should never come into contact with acids. Never resize or repair a ring set with tanzanite because the stone could shatter in the heat of a torch.

New mining techniques and the liberalization of the Tanzanian economy has helped to boost production in the past few years to make tanzanite more available than ever before in the history of the gemstone.

Among the important gems discovered in the last 90 years, only Tanzanite has been added to the official birthstone list. It was adopted as a December birthstone by the American Gem Trade Association and shares that month with turquoise and zircon.

Tanzanites have become very popular and increasingly valuable for two obvious reasons: First of all is the spectacular color? Secondly, the stone is found on only one special location in the entire world. This is what makes it is especially valuable. The desire to own something unique and rare has always been a decisive criterion for assessing the value of special gemstones.


Cultured Fancy Colored Diamonds

Diamonds of the new century - cultured fancy colored diamonds - is the product of New Age Diamonds Inc. that consolidated under this brand a Russian former space lab where HPHT method for producing synthetic gem-quality diamonds originally was developed and applied - and all representative branches.

That is not just one more company trying to amaze the world and unshakeable diamond empire - but the powerful manufacture with wide scope of production where 120 unique high-capacity machines are producing orange, vivid yellow and greenish diamonds, grown in lab but having all chemical, physical and optical properties of real diamonds - and their attraction.

After years of research based on the Russian scientists' investigations with purpose to obtain gem-quality cultured diamonds, as well as the diamonds for technical needs in the field of microelectronics, and innovation of technology New Age Diamonds is ready to enter the market with a new company strategy that includes positive concept of joy-gems.

"Our aim is not to conquer the stable and respectable diamond market, - Mr.Shulepov, the president of New Age Diamonds said, - but to find the new one for our synthetic diamonds, the special niche that definitely exists. The reason to buy New Age Diamonds is obvious - they are as beautiful as real fancy colored diamonds, they have their brilliance and fire - but the price is times less."

Rich intensive colors of these stones give the unique possibilities for contemporary design of jewellery - affordable adornment for new generation, open-minded and new fashion oriented people who don't have any prejudices and can value the beauty and the purity of New Age Diamonds.

For more information: http://www.newagediamonds.com

Learn more about colored diamonds at http://www.diamondsourceva.com/Education/ColoredDiamonds/ColoredDiamonds.asp


Aquamarine

Aquamarine, named for the Latin phrase "water of the sea", is a blue to blue-green variety of the mineral beryl. Beryl also contains other gem varieties, including emerald and some lesser known varieties (such as morganite and heliodor). Light green beryl can be transformed into aquamarine if heated to 750º F (400º C). The green hues in regular aquamarine can also be removed through heating. In fact. almost all aquamarine gems on the market today are heat-treated. Generally, the deeper the blue in aquamarine, the greater its value. A very dark form of beryl resembling deep blue sapphire is artificially formed by irradiating certain beryls. These dark blue stones are not called aquamarine but "blue beryl".

Aquamarine is a fairly common gem, and is thus affordable. Some enormous transparent crystal masses have been exploited, and exquisite gems weighing thousands of carats have been cut from them. The beautiful light blue to blue-green color of aquamarine may fade upon prolonged exposure to light, so it is especially important to purchase this gem from a reliable dealer.

Light blue topaz is easily mistaken for aquamarine. The colors of these two gems are identical, and their physical properties are very similar. Topaz is the less expensive gem, and some crooked dealers may sell their topaz as aquamarine.

Unlike emerald, aquamarine gems are often completely flawless. In fact, an aquamarine gem with a visible flaw is rarely seen. The costs of producing synthetic aquamarine are very high when compared to the relative abundance of this gem, so synthetic aquamarine is not available on the market. However, production of synthetic blue spinel is easy and inexpensive, so it is used as a cheap aquamarine simulant. It is often mistakenly sold as "Synthetic Aquamarine".

Aquamarine is a hard and durable gem, but occasionally develops internal cracks if banged hard. Its color may fade upon prolonged exposure to light.

Aquamarine is faceted into many cuts. It is used in jewelry for rings, earrings, necklaces, etc. Many large, flawless gem pieces have been cut. Occasionally, perfect, flawless, six-sided crystals are worn as necklace pendants. Translucent aquamarine displaying a cat's eye effect and asterism are cut and polished into cabochons.


Beryl

Beryl occurs in a variety of colors. All transparent varieties are used as gemstones. Pure beryl is colorless; traces of different impurities are responsible for the great color range in this gemstone. Each color variety has a distinct name:

Emerald, the green variety, is the most popular green gemstone and is one of the most valuable of gems. A separate page is devoted to this variety.

Aquamarine, a light blue to blue-green variety, also has its own page.

Morganite, the pink to purple variety, is usually only lightly tinted. The color of pale stones can be intensified by heat-treatment. Morganite is sometimes also called "pink beryl".

Heliodor is the variety including all yellow, yellow-green, orange, and brown beryls. Golden beryl, sometimes also called "heliodorite", is a variety of heliodor with a golden yellow color. The terms heliodor and golden beryl are often confused with each other, and some dealers and references incorrectly mix up heliodor and golden beryl.

Goshenite, the colorless variety of beryl, is often used as a replacement for more valuable colorless gems. Goshenite may also be coated with a green foil to resemble emerald, as its physical properties are identical to emerald.

Peach beryl, also known as "champagne beryl", is a variety of morganite with an orange-pink color.

Green beryl, the light green variety of beryl, should not be mistaken for emerald, which occurs in a much darker green. Green beryl is usually heat-treated to form deeply colored aquamarines.

Bixbite is a strawberry-red variety of morganite, with a brownish hue.

Red beryl is a rare, deep red variety found in only one place in the world.

Blue beryl is a dark blue variety, synthetically colored by irradiating light blue aquamarine.

Most of these variety names are universally used, but some, such as bixbite and blue beryl are not well-known. Gem beryls other than emerald and aquamarine may also be called "precious beryl". Internal flaws in beryl gems can be masked by treating the stone with oil. Unscrupulous dealers will often apply this treatment to a stone without informing the buyer.

All the varieties are faceted into various gem cuts, and some stones display asterism and cat's eye effect when cut and polished into cabochons. Ornamental figures are sometimes carved from massive chunks of transparent beryl, usually from morganite and heliodor. Perfect, transparent, six-sided crystals are occasionally worn as necklace pendants in an uncut state.

SIMILAR GEMSTONES

Morganite closely resembles rose quartz, and golden beryl may appear similar to chrysoberyl, and topaz. Heliodor may be confused with many gemstones, especially topaz, chrysoberyl, citrine, and zircon. Goshenite resembles other colorless gemstones, particularly diamond, colorless sapphire, colorless spinel, and rock crystal. Peach beryl has the same appearance as padparadschah (sapphire), some spinels, and some topaz. Green beryl may resemble hiddenite, light green garnet, and light green zircon. Bixbite will have the same color as some topaz and spinel. Red beryl has a distinct red color, darker than ruby or ruby spinel. And finally, blue beryl resembles sapphire and tanzanite.


Chrysoberyl

Chrysoberyl is a hard, tough, and durable gem. Although it lacks fire, specimens are very valuable. Most chrysoberyl gems are yellow, and some are brown or green. A rare, costly variety, known as alexandrite, exhibits different colors in natural and artificial light. If viewed in sunlight, its color is dark yellow-green to greenish-blue. If viewed in artificial light, its color is strawberry-red. Alexandrite was discovered on the birthday of the Russian Czar Alexander II, and was named in his honor.

Another expensive form of chrysoberyl is the unusual cat's eye variety. When polished as cabochons, these stones exhibit a narrow band of concentrated light along the width of the gem. This effect, known as cat's eye effect, is caused by inclusions of fine, slender parallel fibers in the gem. The cat's eye variety may be called "cat's eye", cat's eye, "precious cat's eye", "oriental cat's eye", "catseye", or "chrysoberyl cat's eye". Many other gems also exhibit a cat's eye effect, but only chrysoberyl's cat's eye enjoys the privilege of having the name "cat's eye". (All other gems that exhibit a cat's eye effect must have the gem name preceding, such as "quartz cat's eye", whereas chrysoberyl's cat's eye is known simply as "cat's eye".)

In some chrysoberyl, the cat's eye effect is weak. It appears as a billowy, floating light reflection as opposed to a bright, concentrated band of light. Such chrysoberyl is known as cymophane, and the effect is called "cymophane effect".

All colors of chrysoberyl are faceted as gems for jewelry. The most common color for jewelry is yellow, but brownish and greenish stones are also seen. Alexandrite is faceted with the brilliant and cushion cuts, to make the color change most recognizable. Cat's eye's are cut into cabochons.


Emerald

Emerald, the green variety of the mineral beryl, is the most famous and favored green gemstone. Its beautiful green color, combined with durability and rarity, make it one of the most valuable gemstones. Beryl also contains other, lesser known gem varieties, such as aquamarine and heliodor. Pure beryl is white; emerald's green color is caused by chromium impurities (and occasionally by vanadium impurities). Deep green is the most desired color in emeralds. The paler the color of the emerald, the lesser its value. Pale emeralds are not called emeralds, but "green beryl". They are sometimes heat-treated, in which they become aquamarine.

Emeralds are notorious for their flaws. Flawless stones are very uncommon, and are noted for their great value. Some people actually prefer an emerald with very minute flaws over a flawless emerald, as this proves authenticity of the stone. Many emerald flaws can be hidden by treating the emeralds with oil. Newer, more effective fracture-filling techniques are also practiced. Irradiation of some emerald gems is somewhat effective in removing certain flaws.

Many emerald fakes and doublets are known. Two pale colored stones may be glued together with a deep green paste, creating a stone resembling emerald. Faceted green glass also resembles emerald, and it may be coated with a hard substance to mask its low hardness. Synthetic emeralds are also sold to unwary buyers without them knowing the stone is synthetic. Experts can distinguish all these fakes, and it is especially important to only purchase emeralds from reliable dealers. Experts can also determine if an emerald was treated with oil to mask internal flaws. Generally, unless otherwise specified, it can be assumed that an emerald has been treated with oil.

A rare, prized form of emerald, found only in the Muzo mining district of Colombia, is a very unusual form of this gem. This emerald, known as "Trapiche emerald" is characterized by star-shaped rays that emanate from its center in a hexagonal pattern. These rays appear much like asterism, but, unlike asterism, they are not caused by light reflection from tiny parallel inclusions, but by black carbon impurities that happen to form in the same pattern.

Emerald may develop internal cracks if banged hard or if subject to extreme temperature change. Emeralds that were treated to mask internal flaws should never be cleaned with an ultrasonic jewelry cleaner, nor should they be washed with soap. These practices will remove the oil and expose the hidden internal flaws.

Transparent emeralds are faceted in gem cuts for jewelry, and translucent material is cut and polished into cabochons and beads. Trapiche emeralds are also cut into cabochons, making exquisite jewelry pieces. A very small number of emeralds display asterism and chatoyancy; these too are cut into cabochons.

Emerald is very sensitive to knocks, and the famous emerald cut was developed specifically for this gem to reduce the amount of pressure during cutting.

Emerald is the birthstone of May.


Andradite

Andradite is the most lustrous of all garnets, and its dispersion ("fire") exceeds even that of diamond. There are three gem varieties of andradite:

Demantoid - emerald-green to green variety of andradite

Topazolite - yellow variety of andradite

Melanite - lustrous, opaque black or dark red variety of andradite

The demantoid variety, which is remarkably rare, is the most valuable form of garnet. The combination of its color and fire give it unsurpassed splendor. Demantoid is easily identified by its characteristic "horsetail" inclusions. Demantoid was very popular in the 19th century, but its popularity has decreased because of its rarity and softness. The variety topazolite rarely occurs in crystals large enough to be worth faceting, and is thus rarely seen in jewelry. The variety melanite was once used in mourning jewelry, but does not have any gem use nowadays.