Ruby is a red gemstone that varies from a light pink to a blood red, a variety of the mineral corundum (aluminium oxide). The color is caused mainly by chromium. Its name comes from ruber, Latin for red. Natural rubies are exceptionally rare[specify], but synthetic rubies (sometimes called created ruby) can be manufactured fairly cheaply. Other varieties of gem-quality corundum are called sapphires. It is considered one of the four precious stones, together with the sapphire, the emerald and the diamond.
Rubies are mined in Africa, Asia, Australia, Greenland, Madagascar and North Carolina. They are most often found in Myanmar (Burma), Sri Lanka, Kenya, Madagascar, and Cambodia, but they have also been found in the U.S. states of Montana, North Carolina and South Carolina. The Mogok Valley in Upper Myanmar has produced some of the finest rubies but, in recent years, very few good rubies have been found there. The unique color in Myanmar (Burmese) rubies is described as "pigeon’s blood". They are known in the trade as “Mogok” rubies. In central Myanmar the area of Mong Hsu also produces rubies. The latest ruby deposit to be found in Myanmar is situated in Nam Ya. In 2002 rubies were found in the Waseges River area of Kenya. Sometimes spinels are found along with rubies in the same rocks and are mistaken for rubies. However, fine red spinels may approach the average ruby in value.
Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only diamond is harder (Mohs 10.0 by definition).
All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics, stimulants, or substitutes. Usually the rough stone is heated before cutting. Almost all rubies today are treated in some form (of which heat treatment is the most common practice), and rubies which are completely untreated and still of excellent quality command a large premium. In general we can list the following types of improvements: color alteration, improving transparency by dissolving rutile inclusions, healing of fractures (cracks) or even completely filling them. See Treatments below.
Prices of rubies are primarily determined by color (the brightest and best "red" called Pigeon Blood Red, command a huge premium over other Rubies of similar quality). After Color follows clarity: similar to Diamonds, a clear stone will command a premium, but a Ruby without any needle-like rutile inclusions will indicate the stone has been treated one way or another. Cut and Carat (size) also determine the price approximately like clarity does.
Phenomena
Sometimes rubies show a 3-point or 6-point star. These Rubies are cut into cabochons to display the effect properly. Stars are best visible with a single-light source, and move across the stone as the light moves. Such effects are called asterism and occur when light is reflected off the silk (the rutile inclusions) in a certain way. This is one example where inclusions actually increase the value of a gemstone. Rubies can furthermore show color changes — though this occurs very rarely — and chatoyancy.
Treatments
Improving the quality of gemstones, and thus treating them, has been a practice of all ages. The level of treatment however can differ considerably and impact the price of a gemstone accordingly. Some treatments occur in almost all cases and are (therefore) considered "acceptable" practices. As with most gemstones, the most accepted and most occurring treatment is heat treatment. Although heat treatment affects the price of a top quality ruby, most if not all rubies at the lower end of the market are heat treated. Heat treatment is performed on the rough stones to improve color, remove purple tingle, blue patches and silk. These heat treatments typically occur around temperaturs of 1800°C (3272°F).[1] Some rubies undergo a process of low tube heat, when the stone is heated over charcoal of a temperature of about 1300°C (2372°F) for 20 to 30 minutes. The silk is only partially broken as the color is improved.
A less acceptable treatment, and one which has gained notoriety in recent years is "Lead Glass Filling" of Rubies. By filling the fractures inside the ruby with so-called "lead glass" the transparency of the stone is dramatically improved making previously unsuited rubies now fit for applications in jewelry. The process is typically split into 4 steps:
Rough stones are pre-polished to eradicate all surface impurities that may affect the process
Rough is cleaned with Hydrogen Fluoride
First heating process whereby no fillers are added. The heating process eradicates impurities inside the fractures. Although this can be done at temperatures up to 1400°C (2552°F) it most likely occurs at a temperature of around 900°C (1636°F) since the Rutile silk is still intact
Second heating process in an electrical oven with different chemical additives. Different solutions and mixes have shown to be successful, however mostly lead-containing glass-powder is used at present. The Ruby is dipped into oil, then covered with powder, embedded on a tile and placed in the over where it is heated at around 900°C (1636°F) for one hour in an oxidizing atmosphere. The Orange colored powder transforms upon heating into a transparent to yellow-colored paste, which fills all fractures. After cooling the color of the paste is fully transparent, that dramatically improves the overall transparency of the Ruby.
In case a color needs to be added, the glass powder can be "enhanced" with Copper or other Metal Oxides as well as elements such as Sodium, Calcium, Potassium etc.
The Second heating process can be repeated three to four times consecutively, even applying different mixtures.[2]
Synthetic and imitation rubies
Synthetic rubies have been made since the late 19th century. They have become more common since the work of Auguste Verneuil and the introduction of the flame fusion process. Other processes in which synthetic rubies can be produced are through the Pulling process, flux process, and the hydrothermal process. Most synthetic rubies originate from flame fusion, due to the low costs involved. Synthetic rubies may have no imperfections visible to the naked eye but magnification may reveal curves striae and gas bubbles. The fewer the number and the less obvious the imperfections, the more valuable the ruby is; unless there are no imperfections (i.e., a "perfect" ruby), in which case it will be suspected of being artificial. Dopants are added to some manufactured rubies so they can be identified as synthetic, but most need gemmological testing to determine their origin. Imitation rubies have also been present in the gemstone market for some time. Red spinel, red garnet and even glass have been falsely named as rubies. Trade terms such as balas ruby for red spinel and rubellite for red tourmaline can mislead unsuspecting buyers. Such terms are therefore discouraged from being used by many gemological associations such as the Gemological Institute of America (GIA).
Records
Although pieces of red corundum can be found weighing many kilograms, they are generally not of sufficient quality to be valuable as gemstones. For this reason, auction prices are the best indicator of a stone's true value, and prices do not necessarily correlate with size. As of 2006, the record price paid at auction for a single stone was $5,860,000 for an unnamed 38.12 carat cabochon-cut ruby.[3] However, other stones with potentially greater value may never have been sold at auction.
A synthetic ruby crystal was used to create the first laser (See Ruby laser).
According to Rebbenu Bachya, and the New International Version, the word odem means "ruby" in the verse Exodus 28:17 (referring to a stone on the Hoshen), and was the stone representing the tribe of Reuben. Modern Hebrew has taken this meaning. However, odem actually means earth, and is cognate with Adam; in the middle east, the earth it refers to is certainly reddish, but the Septuagint translates the term as Sard (which also means red), which is also the name of an incredibly common somewhat opaque gem. Scholars think the stone intended is probably a Sard, as does the King James Version, scholars think that if not a Sard it may possibly be the related gem carnelian; it is thought possible that Sard and Odem here just mean the colour of the stone, and red Jasper would therefore also be a possibility. There is a wide range of views among traditional sources about which tribe the stone refers to.
Ruby is the most commonly named precious stone in English translations of the Bible; an example being Proverbs 31: "A virtuous wife is worth more than rubies.". The underlying masoretic text doesn't necessarily refer to rubies, however. Not only are there issues such as that mentioned with odem, but in the case of Proverbs 31, the masoretic text merely states jewels, and the Septuagint makes Proverbs 31 refer to precious stones (estin lithon ); some English versions of the bible believe that pearls is a better translation here.
The famous lighted "Red Stars" mounted above Kremlin spires, thought to be giant rubies mined in Siberia, are actually colored glass.
Ruby is the birthstone associated with July and of the zodiac sign Leo and Cancer.
Ruby is associated with the Sun in vedic astrology.
Ruby symbolizes passionate love.
Although their names bear some similarity, rubies are not related to rubidium, and they don't contain this chemical element. Both names derive from the same Latin word, ruber, meaning red, in reference to the red color of the ruby, and the red resonance line of rubidium vapor, respectively.
this page is from http://en.wikipedia.org/wiki/Ruby All text is available under the terms of the GNU Free Documentation License (http://en.wikipedia.org/wiki/Wikipedia:Copyrights)
Saturday, June 30, 2007
Ruby
Ruby is a red gemstone that varies from a light pink to a blood red, a variety of the mineral corundum (aluminium oxide). The color is caused mainly by chromium. Its name comes from ruber, Latin for red. Natural rubies are exceptionally rare[specify], but synthetic rubies (sometimes called created ruby) can be manufactured fairly cheaply. Other varieties of gem-quality corundum are called sapphires. It is considered one of the four precious stones, together with the sapphire, the emerald and the diamond.
Rubies are mined in Africa, Asia, Australia, Greenland, Madagascar and North Carolina. They are most often found in Myanmar (Burma), Sri Lanka, Kenya, Madagascar, and Cambodia, but they have also been found in the U.S. states of Montana, North Carolina and South Carolina. The Mogok Valley in Upper Myanmar has produced some of the finest rubies but, in recent years, very few good rubies have been found there. The unique color in Myanmar (Burmese) rubies is described as "pigeon’s blood". They are known in the trade as “Mogok” rubies. In central Myanmar the area of Mong Hsu also produces rubies. The latest ruby deposit to be found in Myanmar is situated in Nam Ya. In 2002 rubies were found in the Waseges River area of Kenya. Sometimes spinels are found along with rubies in the same rocks and are mistaken for rubies. However, fine red spinels may approach the average ruby in value.
Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only diamond is harder (Mohs 10.0 by definition).
All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics, stimulants, or substitutes. Usually the rough stone is heated before cutting. Almost all rubies today are treated in some form (of which heat treatment is the most common practice), and rubies which are completely untreated and still of excellent quality command a large premium. In general we can list the following types of improvements: color alteration, improving transparency by dissolving rutile inclusions, healing of fractures (cracks) or even completely filling them. See Treatments below.
Prices of rubies are primarily determined by color (the brightest and best "red" called Pigeon Blood Red, command a huge premium over other Rubies of similar quality). After Color follows clarity: similar to Diamonds, a clear stone will command a premium, but a Ruby without any needle-like rutile inclusions will indicate the stone has been treated one way or another. Cut and Carat (size) also determine the price approximately like clarity does.
Phenomena
Sometimes rubies show a 3-point or 6-point star. These Rubies are cut into cabochons to display the effect properly. Stars are best visible with a single-light source, and move across the stone as the light moves. Such effects are called asterism and occur when light is reflected off the silk (the rutile inclusions) in a certain way. This is one example where inclusions actually increase the value of a gemstone. Rubies can furthermore show color changes — though this occurs very rarely — and chatoyancy.
Treatments
Improving the quality of gemstones, and thus treating them, has been a practice of all ages. The level of treatment however can differ considerably and impact the price of a gemstone accordingly. Some treatments occur in almost all cases and are (therefore) considered "acceptable" practices. As with most gemstones, the most accepted and most occurring treatment is heat treatment. Although heat treatment affects the price of a top quality ruby, most if not all rubies at the lower end of the market are heat treated. Heat treatment is performed on the rough stones to improve color, remove purple tingle, blue patches and silk. These heat treatments typically occur around temperaturs of 1800°C (3272°F).[1] Some rubies undergo a process of low tube heat, when the stone is heated over charcoal of a temperature of about 1300°C (2372°F) for 20 to 30 minutes. The silk is only partially broken as the color is improved.
A less acceptable treatment, and one which has gained notoriety in recent years is "Lead Glass Filling" of Rubies. By filling the fractures inside the ruby with so-called "lead glass" the transparency of the stone is dramatically improved making previously unsuited rubies now fit for applications in jewelry. The process is typically split into 4 steps:
Rough stones are pre-polished to eradicate all surface impurities that may affect the process
Rough is cleaned with Hydrogen Fluoride
First heating process whereby no fillers are added. The heating process eradicates impurities inside the fractures. Although this can be done at temperatures up to 1400°C (2552°F) it most likely occurs at a temperature of around 900°C (1636°F) since the Rutile silk is still intact
Second heating process in an electrical oven with different chemical additives. Different solutions and mixes have shown to be successful, however mostly lead-containing glass-powder is used at present. The Ruby is dipped into oil, then covered with powder, embedded on a tile and placed in the over where it is heated at around 900°C (1636°F) for one hour in an oxidizing atmosphere. The Orange colored powder transforms upon heating into a transparent to yellow-colored paste, which fills all fractures. After cooling the color of the paste is fully transparent, that dramatically improves the overall transparency of the Ruby.
In case a color needs to be added, the glass powder can be "enhanced" with Copper or other Metal Oxides as well as elements such as Sodium, Calcium, Potassium etc.
The Second heating process can be repeated three to four times consecutively, even applying different mixtures.[2]
Synthetic and imitation rubies
Synthetic rubies have been made since the late 19th century. They have become more common since the work of Auguste Verneuil and the introduction of the flame fusion process. Other processes in which synthetic rubies can be produced are through the Pulling process, flux process, and the hydrothermal process. Most synthetic rubies originate from flame fusion, due to the low costs involved. Synthetic rubies may have no imperfections visible to the naked eye but magnification may reveal curves striae and gas bubbles. The fewer the number and the less obvious the imperfections, the more valuable the ruby is; unless there are no imperfections (i.e., a "perfect" ruby), in which case it will be suspected of being artificial. Dopants are added to some manufactured rubies so they can be identified as synthetic, but most need gemmological testing to determine their origin. Imitation rubies have also been present in the gemstone market for some time. Red spinel, red garnet and even glass have been falsely named as rubies. Trade terms such as balas ruby for red spinel and rubellite for red tourmaline can mislead unsuspecting buyers. Such terms are therefore discouraged from being used by many gemological associations such as the Gemological Institute of America (GIA).
Records
Although pieces of red corundum can be found weighing many kilograms, they are generally not of sufficient quality to be valuable as gemstones. For this reason, auction prices are the best indicator of a stone's true value, and prices do not necessarily correlate with size. As of 2006, the record price paid at auction for a single stone was $5,860,000 for an unnamed 38.12 carat cabochon-cut ruby.[3] However, other stones with potentially greater value may never have been sold at auction.
A synthetic ruby crystal was used to create the first laser (See Ruby laser).
According to Rebbenu Bachya, and the New International Version, the word odem means "ruby" in the verse Exodus 28:17 (referring to a stone on the Hoshen), and was the stone representing the tribe of Reuben. Modern Hebrew has taken this meaning. However, odem actually means earth, and is cognate with Adam; in the middle east, the earth it refers to is certainly reddish, but the Septuagint translates the term as Sard (which also means red), which is also the name of an incredibly common somewhat opaque gem. Scholars think the stone intended is probably a Sard, as does the King James Version, scholars think that if not a Sard it may possibly be the related gem carnelian; it is thought possible that Sard and Odem here just mean the colour of the stone, and red Jasper would therefore also be a possibility. There is a wide range of views among traditional sources about which tribe the stone refers to.
Ruby is the most commonly named precious stone in English translations of the Bible; an example being Proverbs 31: "A virtuous wife is worth more than rubies.". The underlying masoretic text doesn't necessarily refer to rubies, however. Not only are there issues such as that mentioned with odem, but in the case of Proverbs 31, the masoretic text merely states jewels, and the Septuagint makes Proverbs 31 refer to precious stones (estin lithon ); some English versions of the bible believe that pearls is a better translation here.
The famous lighted "Red Stars" mounted above Kremlin spires, thought to be giant rubies mined in Siberia, are actually colored glass.
Ruby is the birthstone associated with July and of the zodiac sign Leo and Cancer.
Ruby is associated with the Sun in vedic astrology.
Ruby symbolizes passionate love.
Although their names bear some similarity, rubies are not related to rubidium, and they don't contain this chemical element. Both names derive from the same Latin word, ruber, meaning red, in reference to the red color of the ruby, and the red resonance line of rubidium vapor, respectively.
this page is from http://en.wikipedia.org/wiki/Ruby All text is available under the terms of the GNU Free Documentation License (http://en.wikipedia.org/wiki/Wikipedia:Copyrights)
Rubies are mined in Africa, Asia, Australia, Greenland, Madagascar and North Carolina. They are most often found in Myanmar (Burma), Sri Lanka, Kenya, Madagascar, and Cambodia, but they have also been found in the U.S. states of Montana, North Carolina and South Carolina. The Mogok Valley in Upper Myanmar has produced some of the finest rubies but, in recent years, very few good rubies have been found there. The unique color in Myanmar (Burmese) rubies is described as "pigeon’s blood". They are known in the trade as “Mogok” rubies. In central Myanmar the area of Mong Hsu also produces rubies. The latest ruby deposit to be found in Myanmar is situated in Nam Ya. In 2002 rubies were found in the Waseges River area of Kenya. Sometimes spinels are found along with rubies in the same rocks and are mistaken for rubies. However, fine red spinels may approach the average ruby in value.
Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only diamond is harder (Mohs 10.0 by definition).
All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics, stimulants, or substitutes. Usually the rough stone is heated before cutting. Almost all rubies today are treated in some form (of which heat treatment is the most common practice), and rubies which are completely untreated and still of excellent quality command a large premium. In general we can list the following types of improvements: color alteration, improving transparency by dissolving rutile inclusions, healing of fractures (cracks) or even completely filling them. See Treatments below.
Prices of rubies are primarily determined by color (the brightest and best "red" called Pigeon Blood Red, command a huge premium over other Rubies of similar quality). After Color follows clarity: similar to Diamonds, a clear stone will command a premium, but a Ruby without any needle-like rutile inclusions will indicate the stone has been treated one way or another. Cut and Carat (size) also determine the price approximately like clarity does.
Phenomena
Sometimes rubies show a 3-point or 6-point star. These Rubies are cut into cabochons to display the effect properly. Stars are best visible with a single-light source, and move across the stone as the light moves. Such effects are called asterism and occur when light is reflected off the silk (the rutile inclusions) in a certain way. This is one example where inclusions actually increase the value of a gemstone. Rubies can furthermore show color changes — though this occurs very rarely — and chatoyancy.
Treatments
Improving the quality of gemstones, and thus treating them, has been a practice of all ages. The level of treatment however can differ considerably and impact the price of a gemstone accordingly. Some treatments occur in almost all cases and are (therefore) considered "acceptable" practices. As with most gemstones, the most accepted and most occurring treatment is heat treatment. Although heat treatment affects the price of a top quality ruby, most if not all rubies at the lower end of the market are heat treated. Heat treatment is performed on the rough stones to improve color, remove purple tingle, blue patches and silk. These heat treatments typically occur around temperaturs of 1800°C (3272°F).[1] Some rubies undergo a process of low tube heat, when the stone is heated over charcoal of a temperature of about 1300°C (2372°F) for 20 to 30 minutes. The silk is only partially broken as the color is improved.
A less acceptable treatment, and one which has gained notoriety in recent years is "Lead Glass Filling" of Rubies. By filling the fractures inside the ruby with so-called "lead glass" the transparency of the stone is dramatically improved making previously unsuited rubies now fit for applications in jewelry. The process is typically split into 4 steps:
Rough stones are pre-polished to eradicate all surface impurities that may affect the process
Rough is cleaned with Hydrogen Fluoride
First heating process whereby no fillers are added. The heating process eradicates impurities inside the fractures. Although this can be done at temperatures up to 1400°C (2552°F) it most likely occurs at a temperature of around 900°C (1636°F) since the Rutile silk is still intact
Second heating process in an electrical oven with different chemical additives. Different solutions and mixes have shown to be successful, however mostly lead-containing glass-powder is used at present. The Ruby is dipped into oil, then covered with powder, embedded on a tile and placed in the over where it is heated at around 900°C (1636°F) for one hour in an oxidizing atmosphere. The Orange colored powder transforms upon heating into a transparent to yellow-colored paste, which fills all fractures. After cooling the color of the paste is fully transparent, that dramatically improves the overall transparency of the Ruby.
In case a color needs to be added, the glass powder can be "enhanced" with Copper or other Metal Oxides as well as elements such as Sodium, Calcium, Potassium etc.
The Second heating process can be repeated three to four times consecutively, even applying different mixtures.[2]
Synthetic and imitation rubies
Synthetic rubies have been made since the late 19th century. They have become more common since the work of Auguste Verneuil and the introduction of the flame fusion process. Other processes in which synthetic rubies can be produced are through the Pulling process, flux process, and the hydrothermal process. Most synthetic rubies originate from flame fusion, due to the low costs involved. Synthetic rubies may have no imperfections visible to the naked eye but magnification may reveal curves striae and gas bubbles. The fewer the number and the less obvious the imperfections, the more valuable the ruby is; unless there are no imperfections (i.e., a "perfect" ruby), in which case it will be suspected of being artificial. Dopants are added to some manufactured rubies so they can be identified as synthetic, but most need gemmological testing to determine their origin. Imitation rubies have also been present in the gemstone market for some time. Red spinel, red garnet and even glass have been falsely named as rubies. Trade terms such as balas ruby for red spinel and rubellite for red tourmaline can mislead unsuspecting buyers. Such terms are therefore discouraged from being used by many gemological associations such as the Gemological Institute of America (GIA).
Records
Although pieces of red corundum can be found weighing many kilograms, they are generally not of sufficient quality to be valuable as gemstones. For this reason, auction prices are the best indicator of a stone's true value, and prices do not necessarily correlate with size. As of 2006, the record price paid at auction for a single stone was $5,860,000 for an unnamed 38.12 carat cabochon-cut ruby.[3] However, other stones with potentially greater value may never have been sold at auction.
A synthetic ruby crystal was used to create the first laser (See Ruby laser).
According to Rebbenu Bachya, and the New International Version, the word odem means "ruby" in the verse Exodus 28:17 (referring to a stone on the Hoshen), and was the stone representing the tribe of Reuben. Modern Hebrew has taken this meaning. However, odem actually means earth, and is cognate with Adam; in the middle east, the earth it refers to is certainly reddish, but the Septuagint translates the term as Sard (which also means red), which is also the name of an incredibly common somewhat opaque gem. Scholars think the stone intended is probably a Sard, as does the King James Version, scholars think that if not a Sard it may possibly be the related gem carnelian; it is thought possible that Sard and Odem here just mean the colour of the stone, and red Jasper would therefore also be a possibility. There is a wide range of views among traditional sources about which tribe the stone refers to.
Ruby is the most commonly named precious stone in English translations of the Bible; an example being Proverbs 31: "A virtuous wife is worth more than rubies.". The underlying masoretic text doesn't necessarily refer to rubies, however. Not only are there issues such as that mentioned with odem, but in the case of Proverbs 31, the masoretic text merely states jewels, and the Septuagint makes Proverbs 31 refer to precious stones (estin lithon ); some English versions of the bible believe that pearls is a better translation here.
The famous lighted "Red Stars" mounted above Kremlin spires, thought to be giant rubies mined in Siberia, are actually colored glass.
Ruby is the birthstone associated with July and of the zodiac sign Leo and Cancer.
Ruby is associated with the Sun in vedic astrology.
Ruby symbolizes passionate love.
Although their names bear some similarity, rubies are not related to rubidium, and they don't contain this chemical element. Both names derive from the same Latin word, ruber, meaning red, in reference to the red color of the ruby, and the red resonance line of rubidium vapor, respectively.
this page is from http://en.wikipedia.org/wiki/Ruby All text is available under the terms of the GNU Free Documentation License (http://en.wikipedia.org/wiki/Wikipedia:Copyrights)
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