Ju Duoqi's exhibition, 'The Vegetable Museum', has just opened at the Paris-Beijing Photo Gallery at the 798 art district in Beijing. A must visit.
Useful links:
www.parisbeijingphotogallery.com
www.798space.com
Friday, November 28, 2008
Imitation Turquoise
(via Wikipedia) The Egyptians were the first to produce an artificial imitation of turquoise, in the glazed earthenware product faience. Later glass and enamel were also used, and in modern times more sophisticated ceramics, porcelain, plastics, and various assembled, pressed, bonded, and sintered products (composed of various copper and aluminium compounds) have been developed: examples of the latter include "Viennese turquoise", made from precipitated aluminium phosphate coloured by copper oleate; and "neolith", a mixture of bayerite and copper phosphate. Most of these products differ markedly from natural turquoise in both physical and chemical properties, but in 1972 Pierre Gilson introduced one fairly close to a true synthetic (it does differ in chemical composition owing to a binder used, meaning it is best described as a simulant rather than a synthetic). Gilson turquoise is made in both a uniform colour and with black "spiderweb matrix" veining not unlike the natural Nevada material.
The most common imitation of turquoise encountered today is dyed howlite and magnesite, both white in their natural states, and the former also having natural (and convincing) black veining similar to that of turquoise. Dyed chalcedony, jasper, and marble is less common, and much less convincing. Other natural materials occasionally confused with or used in lieu of turquoise include: variscite and faustite; chrysocolla (especially when impregnating quartz); lazulite; smithsonite; hemimorphite; wardite; and a fossil bone or tooth called odontolite or "bone turquoise", coloured blue naturally by the mineral vivianite. While rarely encountered today, odontolite was once mined in large quantities—specifically for its use as a substitute for turquoise—in southern France.
These fakes are detected by gemmologists using a number of tests, relying primarily on non-destructive, close examination of surface structure under magnification; a featureless, pale blue background peppered by flecks or spots of whitish material is the typical surface appearance of natural turquoise, while manufactured imitations will appear radically different in both colour (usually a uniform dark blue) and texture (usually granular or sugary). Glass and plastic will have a much greater translucency, with bubbles or flow lines often visible just below the surface. Staining between grain boundaries may be visible in dyed imitations.
Some destructive tests may, however, be necessary; for example, the application of diluted hydrochloric acid will cause the carbonates odontolite and magnesite to effervesce and howlite to turn green, while a heated probe may give rise to the pungent smell so indicative of plastic. Differences in specific gravity, refractive index, light absorption (as evident in a material's absorption spectrum), and other physical and optical properties are also considered as means of separation. Imitation turquoise is so prevalent that it likely outnumbers real turquoise by a wide margin. Even material used in authentic Native American and Tibetan jewellery is often fake or, at best, heavily treated.
http://en.wikipedia.org/wiki/Turquoise
Today China has become an important source for imitation turquoise. The opaque bead materials are mass produced, inexpensive, and found in gem markets worldwide. If in doubt, always consult a reputed gem testing laboratory.
The most common imitation of turquoise encountered today is dyed howlite and magnesite, both white in their natural states, and the former also having natural (and convincing) black veining similar to that of turquoise. Dyed chalcedony, jasper, and marble is less common, and much less convincing. Other natural materials occasionally confused with or used in lieu of turquoise include: variscite and faustite; chrysocolla (especially when impregnating quartz); lazulite; smithsonite; hemimorphite; wardite; and a fossil bone or tooth called odontolite or "bone turquoise", coloured blue naturally by the mineral vivianite. While rarely encountered today, odontolite was once mined in large quantities—specifically for its use as a substitute for turquoise—in southern France.
These fakes are detected by gemmologists using a number of tests, relying primarily on non-destructive, close examination of surface structure under magnification; a featureless, pale blue background peppered by flecks or spots of whitish material is the typical surface appearance of natural turquoise, while manufactured imitations will appear radically different in both colour (usually a uniform dark blue) and texture (usually granular or sugary). Glass and plastic will have a much greater translucency, with bubbles or flow lines often visible just below the surface. Staining between grain boundaries may be visible in dyed imitations.
Some destructive tests may, however, be necessary; for example, the application of diluted hydrochloric acid will cause the carbonates odontolite and magnesite to effervesce and howlite to turn green, while a heated probe may give rise to the pungent smell so indicative of plastic. Differences in specific gravity, refractive index, light absorption (as evident in a material's absorption spectrum), and other physical and optical properties are also considered as means of separation. Imitation turquoise is so prevalent that it likely outnumbers real turquoise by a wide margin. Even material used in authentic Native American and Tibetan jewellery is often fake or, at best, heavily treated.
http://en.wikipedia.org/wiki/Turquoise
Today China has become an important source for imitation turquoise. The opaque bead materials are mass produced, inexpensive, and found in gem markets worldwide. If in doubt, always consult a reputed gem testing laboratory.
Herding Behavior
(via dailyspeculations) Vinh Tu writes:
Virtual birds form flocks, when each bird individually follows three rules:
1. Separation: steer to avoid crowding local flockmates.
2. Alignment: steer towards the average heading of local flockmates.
3. Cohesion: steer to move toward the average position of local flockmates
Demo @ http://www.red3d.com/cwr/boids
I liked it. Thanks Vinh Tu.
Virtual birds form flocks, when each bird individually follows three rules:
1. Separation: steer to avoid crowding local flockmates.
2. Alignment: steer towards the average heading of local flockmates.
3. Cohesion: steer to move toward the average position of local flockmates
Demo @ http://www.red3d.com/cwr/boids
I liked it. Thanks Vinh Tu.
Diamonds: Best Case Scenario Forecast
Chaim Even Zohar's viewpoints on best case scenario forecast for diamond jewelry @ http://www.idexonline.com/portal_FullEditorial.asp was insightful. A must read.
Bringit
Challenge + Play + Earn = http://bringit.com
An interesting site for die-hards to test their skills. I think.
An interesting site for die-hards to test their skills. I think.
Best Business Books Of 2008
Fast Company: The Best Business Books of 2008
http://www.fastcompany.com/multimedia/slideshows/content/books-2008.html?page=1
http://www.fastcompany.com/multimedia/slideshows/content/books-2008.html?page=1
Notable Books Of 2008
New York Times: The Book Review - 100 Notable Books of 2008
http://www.nytimes.com/2008/12/07/books/review/100Notable-t.html?pagewanted=1&_r=1
http://www.nytimes.com/2008/12/07/books/review/100Notable-t.html?pagewanted=1&_r=1
Thursday, November 27, 2008
Australia
Australia
Director: Baz Luhrmann
Nicole Kidman + Hugh Jackman light up the screen in the movie Australia. I am a huge Baz Luhrmann fan. I think Baz has pulled off another huge success. A must see movie, really.
Useful links:
www.australiamovie.com
www.australia.com
www.bazthegreatsite.com
Director: Baz Luhrmann
Nicole Kidman + Hugh Jackman light up the screen in the movie Australia. I am a huge Baz Luhrmann fan. I think Baz has pulled off another huge success. A must see movie, really.
Useful links:
www.australiamovie.com
www.australia.com
www.bazthegreatsite.com
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