(via Wikipedia) Madagascar, or Republic of Madagascar (older name Malagasy Republic), is an island nation in the Indian Ocean off the southeastern coast of Africa. The main island, also called Madagascar, is the fourth largest island in the world, and is home to five percent of the world's plant and animal species; more than 80 percent of which are endemic to Madagascar. Most notable are the lemur infraorder of primates, the carnivorous fossa, three endemic bird families and six endemic baobab species + the entire country is rich in colored gemstones.
Useful links:
http://en.wikipedia.org/wiki/Madagascar
http://www.lonelyplanet.com/worldguide/destinations/africa/madagascar
Sunday, November 11, 2007
Enrico Caruso
Enrico Caruso was an Italian opera singer + one of the most famous tenors in history. I enjoy the music + listening to Caruso's songs + his extraordinary voice + the natural tone is inspirational and therapeutic. He was a superstar of his time but the music still lives on.
Enrico Caruso songs:
La donna è mobile
Ave Maria
Vesti La Giubba
No Pagliaccio non son
La Partida
O Sole Mio
Santa Lucia
(via Henry Rosner) Hear Enrico Caruso sing Vesti la giubba from "I Pagliacci, Act 1" 17 March 1907 (in mp3 format)
More information about Enrico Caruso's recordings @ Enrico Caruso recordings.
Enrico Caruso songs:
La donna è mobile
Ave Maria
Vesti La Giubba
No Pagliaccio non son
La Partida
O Sole Mio
Santa Lucia
(via Henry Rosner) Hear Enrico Caruso sing Vesti la giubba from "I Pagliacci, Act 1" 17 March 1907 (in mp3 format)
More information about Enrico Caruso's recordings @ Enrico Caruso recordings.
Saturday, November 10, 2007
The Emerald Story
The main cuts employed for emeralds
Step/Emerald cut: This is the most important and popular cut employed for emeralds. All facets are cut in squares or rectangles which are arranged in steps, giving an elongated octagonal outline. The best quality emeralds are almost universally fashioned in this way for these reasons:
- It shows the saturated deep velvety-green of emerald to the best advantage. Since color is the most important determinant of value in emeralds, a stone with a good depth of color fetches a higher market price than one that does not.
- The step cut minimizes loss of mass during cutting and polishing. This means more carat weight retention of the stone and hence value (value = price/carat x carat weight).
Mixed cut: The crown of the stone is brilliant cut, while the pavilion is step cut. It is not very popular since it gives the stone a pale glassy look, which is not desirable.
Cabochon & beads: Stones which are turbid and heavily included and are of good color are commonly cut as cabochons and beads. A cabochon may have a flat base and a dome-shaped upper portion. Emeralds cut in this manner are usually sub-transparent to opaque, and can range from light to very dark green. Emeralds of low to medium quality are thus fashioned. Emerald beads and cabochons are becoming increasingly popular since they are a beautiful yet inexpensive form of natural emeralds.
Fancy cuts and carvings: Heavily included emeralds with good color but limited transparency are an excellent base for carving. Carved emeralds are fashioned into pendants, belt-buckles, and show pieces in a variety of exotic jewelry.
The cut of a stone is crucial to its color and beauty, and has great influence on its ultimate value.
Common treatments applied to emeralds
Mining, cutting, faceting, and polishing procedures are accepted and considered, as the normal processing of gemstones. However, in his endeavor to enhance value, man has subjected his gems to further treatments. Some of the treatments are necessary and are now accepted as normal processing for a gemstone, while others are subject to disclosure.
The common treatments for emeralds are oiling, staining/dyeing and resin impregnation.
Oiling: Perhaps the most universal treatment for emeralds, practised by emerald dealers all over the world. This treatment is more of a finishing touch applied to emeralds of good color but with visible internal fissures. Oiling enhances surface shine and luster, and reduces the visibility of fissures in the stone, thereby adding to its saleability.
Oils used: Cedarwood oil, Canada Balsam, mineral oil.
Method: The method of oiling varies from dealer to dealer, with much being kept secret for obvious reasons. But basically, it involves these steps: (a) Emeralds are first cleaned thoroughly using a mild acid (b) They are then soaked in warm clear oil (Cedar oil is popular) and subjected to appropriate heat and sometimes pressure or vacuum.
Effect: The oil permeates into the fissures and fills them, reducing their visibility. Modern oiling machines offer an easily and effective treatment method for emeralds.
Durability of treatment: The oil comes out of the fissures when subjected to heat, ultrasonic cleansing, immersion in soapy water or acids, alcohol or other solvents. Otherwise, for normal wear and tear, it remains stable for a reasonable period of time. Stones can be re-oiled if necessary.
The practice of oiling is so prevalent that it is hard to curb. It is regarded as standard practice. But since the effect is not 100% permanent, trade organizations and gem testing laboratories encourages disclosure of the treatment to customers upon purchase.
Detection of oiling under the microscope: Traces of oil may be seen in fissures when the stone is viewed under the microscope. Typical signs of oiling are:
- Low relief of fissures that would otherwise appear white. Some fissures tend to appear shiny (fluid-like) when viewed at certain angles.
- Flattened gas bubbles trapped in the filling media (oil)
- Some oils fluoresce (emit light) when subjected to ultra-violet (UV) radiation. For e.g. Canada Balsam shows a weak greenish yellow light under UV.
Staining/dyeing: Yet another age-old technique to enhance the appearance of a gem that is commonly applied to emeralds. Whereas the main motive for oiling an emerald is to conceal fissures, the main aim of dyeing an emerald is to give a false appearance of color in otherwise pale-colored emeralds. The dyeing of colorless beryl to simulate the appearance of emerald is also carried out. Staining or dyeing may be either a surface only treatment or it may penetrate fissures.
Dyes used: Natural organic dyes, synthetic dyes (e.g. aniline) compounds of metallic salts.
Method: (a) The stone is thoroughly cleaned. (b) The stone is soaked in oil containing the green dye at an appropriate temperature for a few hours.
Effect: The green oil permeates into the stone increasing depth of color, and reducing the visibility of internal fissures.
Durability of treatment: Natural organic dyes are least stable and some deteriorate easily. Synthetic dyes tend to last longer. Certain dyes don’t come out of the fissures even if the oil wears off when subject to heat or alcohol.
Status of treatment: Since dyeing significantly alters the appearance of emeralds and possibly other beryls and is not permanent, this treatment should be disclosed to customers upon purchase.
Detection of treatment: One can always detect the presence of dye under magnification. Indications are: (a) Color concentration in fissures and chips, (b) Slightly colored outlining of fissures, (c) Uneven color distribution, (d) Some colored oils fluoresce under UV radiation.
Resin impregnation of fissures (Opticon treatment): A relatively recent development in the treatment of emeralds. It involves impregnating fissures with a synthetic resin marketed as Opticon. Opticon, as a resin, is more durable than oil, making the treatment more permanent. It is a two part product consisting of the resin itself plus a separate hardener (an additional fluid which when added to the resin causes it to become hard). A vacuum is usually used to assist the flow of the resin into the fissures in emerald. Sometimes the treater will then add the hardener and sometimes not.
Detection of the treatment: Many resins, including Opticon can be detected by the observation of blue and yellow/orange color flashes coming from the region of treated fissures. Positive identification can come from Raman spectroscopy available only in the best equipped gem labs.
Status of treatment: If no hardener is applied, whilst this resin treatment might be a little more stable than oiling it is still not permanent. If a hardener is applied this may cause fissures to expand under warm conditions, or when being repolished, which may result in severe damage-occurring. Hence, disclosure of treatment is required.
Emerald Story (continued)
Step/Emerald cut: This is the most important and popular cut employed for emeralds. All facets are cut in squares or rectangles which are arranged in steps, giving an elongated octagonal outline. The best quality emeralds are almost universally fashioned in this way for these reasons:
- It shows the saturated deep velvety-green of emerald to the best advantage. Since color is the most important determinant of value in emeralds, a stone with a good depth of color fetches a higher market price than one that does not.
- The step cut minimizes loss of mass during cutting and polishing. This means more carat weight retention of the stone and hence value (value = price/carat x carat weight).
Mixed cut: The crown of the stone is brilliant cut, while the pavilion is step cut. It is not very popular since it gives the stone a pale glassy look, which is not desirable.
Cabochon & beads: Stones which are turbid and heavily included and are of good color are commonly cut as cabochons and beads. A cabochon may have a flat base and a dome-shaped upper portion. Emeralds cut in this manner are usually sub-transparent to opaque, and can range from light to very dark green. Emeralds of low to medium quality are thus fashioned. Emerald beads and cabochons are becoming increasingly popular since they are a beautiful yet inexpensive form of natural emeralds.
Fancy cuts and carvings: Heavily included emeralds with good color but limited transparency are an excellent base for carving. Carved emeralds are fashioned into pendants, belt-buckles, and show pieces in a variety of exotic jewelry.
The cut of a stone is crucial to its color and beauty, and has great influence on its ultimate value.
Common treatments applied to emeralds
Mining, cutting, faceting, and polishing procedures are accepted and considered, as the normal processing of gemstones. However, in his endeavor to enhance value, man has subjected his gems to further treatments. Some of the treatments are necessary and are now accepted as normal processing for a gemstone, while others are subject to disclosure.
The common treatments for emeralds are oiling, staining/dyeing and resin impregnation.
Oiling: Perhaps the most universal treatment for emeralds, practised by emerald dealers all over the world. This treatment is more of a finishing touch applied to emeralds of good color but with visible internal fissures. Oiling enhances surface shine and luster, and reduces the visibility of fissures in the stone, thereby adding to its saleability.
Oils used: Cedarwood oil, Canada Balsam, mineral oil.
Method: The method of oiling varies from dealer to dealer, with much being kept secret for obvious reasons. But basically, it involves these steps: (a) Emeralds are first cleaned thoroughly using a mild acid (b) They are then soaked in warm clear oil (Cedar oil is popular) and subjected to appropriate heat and sometimes pressure or vacuum.
Effect: The oil permeates into the fissures and fills them, reducing their visibility. Modern oiling machines offer an easily and effective treatment method for emeralds.
Durability of treatment: The oil comes out of the fissures when subjected to heat, ultrasonic cleansing, immersion in soapy water or acids, alcohol or other solvents. Otherwise, for normal wear and tear, it remains stable for a reasonable period of time. Stones can be re-oiled if necessary.
The practice of oiling is so prevalent that it is hard to curb. It is regarded as standard practice. But since the effect is not 100% permanent, trade organizations and gem testing laboratories encourages disclosure of the treatment to customers upon purchase.
Detection of oiling under the microscope: Traces of oil may be seen in fissures when the stone is viewed under the microscope. Typical signs of oiling are:
- Low relief of fissures that would otherwise appear white. Some fissures tend to appear shiny (fluid-like) when viewed at certain angles.
- Flattened gas bubbles trapped in the filling media (oil)
- Some oils fluoresce (emit light) when subjected to ultra-violet (UV) radiation. For e.g. Canada Balsam shows a weak greenish yellow light under UV.
Staining/dyeing: Yet another age-old technique to enhance the appearance of a gem that is commonly applied to emeralds. Whereas the main motive for oiling an emerald is to conceal fissures, the main aim of dyeing an emerald is to give a false appearance of color in otherwise pale-colored emeralds. The dyeing of colorless beryl to simulate the appearance of emerald is also carried out. Staining or dyeing may be either a surface only treatment or it may penetrate fissures.
Dyes used: Natural organic dyes, synthetic dyes (e.g. aniline) compounds of metallic salts.
Method: (a) The stone is thoroughly cleaned. (b) The stone is soaked in oil containing the green dye at an appropriate temperature for a few hours.
Effect: The green oil permeates into the stone increasing depth of color, and reducing the visibility of internal fissures.
Durability of treatment: Natural organic dyes are least stable and some deteriorate easily. Synthetic dyes tend to last longer. Certain dyes don’t come out of the fissures even if the oil wears off when subject to heat or alcohol.
Status of treatment: Since dyeing significantly alters the appearance of emeralds and possibly other beryls and is not permanent, this treatment should be disclosed to customers upon purchase.
Detection of treatment: One can always detect the presence of dye under magnification. Indications are: (a) Color concentration in fissures and chips, (b) Slightly colored outlining of fissures, (c) Uneven color distribution, (d) Some colored oils fluoresce under UV radiation.
Resin impregnation of fissures (Opticon treatment): A relatively recent development in the treatment of emeralds. It involves impregnating fissures with a synthetic resin marketed as Opticon. Opticon, as a resin, is more durable than oil, making the treatment more permanent. It is a two part product consisting of the resin itself plus a separate hardener (an additional fluid which when added to the resin causes it to become hard). A vacuum is usually used to assist the flow of the resin into the fissures in emerald. Sometimes the treater will then add the hardener and sometimes not.
Detection of the treatment: Many resins, including Opticon can be detected by the observation of blue and yellow/orange color flashes coming from the region of treated fissures. Positive identification can come from Raman spectroscopy available only in the best equipped gem labs.
Status of treatment: If no hardener is applied, whilst this resin treatment might be a little more stable than oiling it is still not permanent. If a hardener is applied this may cause fissures to expand under warm conditions, or when being repolished, which may result in severe damage-occurring. Hence, disclosure of treatment is required.
Emerald Story (continued)
Memories Of Spain
(via The Guardian) James Fenton writes about the Hispanic Society of America, on West 155th Street in Manhattan (USA) + Archer Milton Huntington + his passion + other viewpoints @ http://arts.guardian.co.uk/art/visualart/story/0,,2204239,00.html
The Real Thing?
Ann Landi writes about contemporary realism + handful of mature artists pursuing realist idiom of one stripe or another + the impact + other viewpoints @ http://artnews.com/issues/article.asp?art_id=1150
The Burgundian Point Cut
(via Diamond Cuts in Historic Jewelry:1381-1910) Herbert Tillander writes:
A Refined Dodecahedron
In the days when superstition prevailed, a cutter could evade the strict rules which controlled the shapes of fashioned diamonds if he had a particularly well developed dodecahedron at his disposal. The four rhombic faces of such a crystal, chosen to face the viewer, could be smoothed and polished at a minimal angle of inclination, thus preserving the shape of a natural crystal.
Crystals fashioned in this way, side by side with Pyramidal Points and Table Cuts, were entirely acceptable and considered ideal as talismans. The Court Goblet of the Duchy of Burgundy in the Vienna Hofburg, with its numerous early and mid-fifteenth century diamonds, is our foremost source of information on cuts of the period. It also indicates that fashioning had been fully mastered by then.
The majority of the larger diamonds display brilliance in the modern sense of the term. This means that by the early fifteenth century cutters had discovered the property inherent in diamonds of reflecting the rays of light from pavilion facets set at correct angles of inclination. Fortunately for posterity, princes of refined taste appreciated these sparkling qualities of diamonds, although at the time fashion still demanded pyramidal shapes and Table Cuts, disapproving of brilliance.
The Burgundian is also exceptional in that it became a prototype which could, simply by means of additional faceting, be transformed into a number of other patterns: the Pointed Star, the Taille en Seize, and finally the Baroque type of Brilliant cut. It was also economical, since it could be fashioned on the wheel alone, and therefore with comparatively little loss of weight.
At first, the pavilion did not differ very much from the crown, but when strictly crystal-like shapes were no longer challenged, the cutters were free to fashion the pavilions differently—depending, of course, on the symmetry of the crystal and the presence of disturbing inclusions in the lower part of the gem.
As a rule, natural dodecahedrons have distinctly rounded faces and sharp, curved edges. Symmetrization of these faces presented no problems to the cutters. The corners were frequently left blunt and were partly hidden by the setting, so that regular crystals could be made to appear almost perfectly round or oval or lozenge-shaped. They were about 25 per cent lower than Pyramidal Point Cuts, but looked lower still because of their semi-spherical appearance. In addition to an amazing amount of brilliance, many of the fashioned gems also displayed fire. Easily identified in contemporary inventories, they are frequently described as having four main lozenge-shaped facets in the center, surrounded by eight semi-lozenges—i.e. Lozenges split into two triangles. In many cases they are described simply as faceted diamonds with an adjective indicating the outline.
As the fashion for Table Cuts (both traditional and more exotically faceted) grew, the apexes of many Burgundian Cuts were ground down. Later, most of the remaining stones of this type were re-cut, the larger sizes into Baroque Brilliants and some smaller ones into matching complementary Double Cuts. This explains why so few Burgundian Point Cuts have survived in their original form.
Fortunately, there are two on the Burgundian Court Goblet. The larger gem, which is about 8.7 mm in diameter, is in a separate setting. In 1621 it was described as ‘Ain Diamant spitzig sternweiss geschnitten (a pointed diamond cut like a star)’. The smaller gem, about 5 x 3 mm in size, forms part of a fleur-de-lis.
An illustration by an artist from Basel, drawn in about 1500, shows a Burgandian Cut on another famous jewel belonging to Charles the Bold, the Feather, thought to have been made in the 1460s. The stone, which must have been about 12.5 mm in diameter, with a weight of about 6 ct, can be seen very clearly in the sales document drawn up between the City of Basel and Fugger’s, and was described as ‘ein demant mit faceten, gutt wasser, nit rein, vol swartzer bunten’.
There is one other illustration of a jewel covered with diamonds of this type. This is a sketch drawn, according to Erna von Watzdorf, by G.C Dinglinger, the less talented brother of the famous Johann Melchior Dinglinger. The drawing is said to date from as late as 1719, when this type of cut was already out of fashion.
A Refined Dodecahedron
In the days when superstition prevailed, a cutter could evade the strict rules which controlled the shapes of fashioned diamonds if he had a particularly well developed dodecahedron at his disposal. The four rhombic faces of such a crystal, chosen to face the viewer, could be smoothed and polished at a minimal angle of inclination, thus preserving the shape of a natural crystal.
Crystals fashioned in this way, side by side with Pyramidal Points and Table Cuts, were entirely acceptable and considered ideal as talismans. The Court Goblet of the Duchy of Burgundy in the Vienna Hofburg, with its numerous early and mid-fifteenth century diamonds, is our foremost source of information on cuts of the period. It also indicates that fashioning had been fully mastered by then.
The majority of the larger diamonds display brilliance in the modern sense of the term. This means that by the early fifteenth century cutters had discovered the property inherent in diamonds of reflecting the rays of light from pavilion facets set at correct angles of inclination. Fortunately for posterity, princes of refined taste appreciated these sparkling qualities of diamonds, although at the time fashion still demanded pyramidal shapes and Table Cuts, disapproving of brilliance.
The Burgundian is also exceptional in that it became a prototype which could, simply by means of additional faceting, be transformed into a number of other patterns: the Pointed Star, the Taille en Seize, and finally the Baroque type of Brilliant cut. It was also economical, since it could be fashioned on the wheel alone, and therefore with comparatively little loss of weight.
At first, the pavilion did not differ very much from the crown, but when strictly crystal-like shapes were no longer challenged, the cutters were free to fashion the pavilions differently—depending, of course, on the symmetry of the crystal and the presence of disturbing inclusions in the lower part of the gem.
As a rule, natural dodecahedrons have distinctly rounded faces and sharp, curved edges. Symmetrization of these faces presented no problems to the cutters. The corners were frequently left blunt and were partly hidden by the setting, so that regular crystals could be made to appear almost perfectly round or oval or lozenge-shaped. They were about 25 per cent lower than Pyramidal Point Cuts, but looked lower still because of their semi-spherical appearance. In addition to an amazing amount of brilliance, many of the fashioned gems also displayed fire. Easily identified in contemporary inventories, they are frequently described as having four main lozenge-shaped facets in the center, surrounded by eight semi-lozenges—i.e. Lozenges split into two triangles. In many cases they are described simply as faceted diamonds with an adjective indicating the outline.
As the fashion for Table Cuts (both traditional and more exotically faceted) grew, the apexes of many Burgundian Cuts were ground down. Later, most of the remaining stones of this type were re-cut, the larger sizes into Baroque Brilliants and some smaller ones into matching complementary Double Cuts. This explains why so few Burgundian Point Cuts have survived in their original form.
Fortunately, there are two on the Burgundian Court Goblet. The larger gem, which is about 8.7 mm in diameter, is in a separate setting. In 1621 it was described as ‘Ain Diamant spitzig sternweiss geschnitten (a pointed diamond cut like a star)’. The smaller gem, about 5 x 3 mm in size, forms part of a fleur-de-lis.
An illustration by an artist from Basel, drawn in about 1500, shows a Burgandian Cut on another famous jewel belonging to Charles the Bold, the Feather, thought to have been made in the 1460s. The stone, which must have been about 12.5 mm in diameter, with a weight of about 6 ct, can be seen very clearly in the sales document drawn up between the City of Basel and Fugger’s, and was described as ‘ein demant mit faceten, gutt wasser, nit rein, vol swartzer bunten’.
There is one other illustration of a jewel covered with diamonds of this type. This is a sketch drawn, according to Erna von Watzdorf, by G.C Dinglinger, the less talented brother of the famous Johann Melchior Dinglinger. The drawing is said to date from as late as 1719, when this type of cut was already out of fashion.
An Engagement And Wedding Web Site For Men
Groomgroove.com, an engagement and wedding web site for men is an interesting concept + the calculator allows the groom to enter his gross salary + calculate what he should spend on a diamond engagement ring + provides information for the groom-to-be on how to buy an engagement ring + other infos.
A brilliant idea.
A brilliant idea.
The Definition Of A Gem Mine
The owner of a gem mine in Southeast Asia told me the definition of a gem mine: 'It's a hole in the ground with a bunch of liars standing around the hole looking down into it.'
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