- Goldfinger
- The Italian Job
- The Maltese Falcon
- The Lavender Hill Mob.
Tuesday, June 26, 2007
Tax Amnesty: Veni, Vidi, Vici
Chaim Even-Zohar writes about the concept of inventory revaluation introduced by the Diamond High Council (HRD) and the Belgian government + the accounting practices applied in the diamond sector between second world war and 1995 + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=26738
How Doctors Think
Most physicians already have in mind two or three possible diagnoses within minutes of meeting a patient. Jerome Groopman writes about the concept of cognitive dimension of clinical decision-making—the process by which doctors interpret their patients’ symptoms and weigh test results in order to arrive at a diagnosis and a plan of treatment @ http://www.newyorker.com/reporting/2007/01/29/070129fa_fact_groopman
It is interesting to analyze the similarity of clinical decision making by doctors with gem identification. The experts have a sweet way of describing the process. Gem identification is a logical process of deduction or alternatively of elimination. The gemologist performs a series of observations and tests upon a particular stone and with each test will eliminate some of the possible identities of that stone. Finally through step-by-step testing only one identity will fit the stone in question. This is the end point of the exercise, to identify an unknown material in terms of its mineralogical group, species and variety.
It is interesting to analyze the similarity of clinical decision making by doctors with gem identification. The experts have a sweet way of describing the process. Gem identification is a logical process of deduction or alternatively of elimination. The gemologist performs a series of observations and tests upon a particular stone and with each test will eliminate some of the possible identities of that stone. Finally through step-by-step testing only one identity will fit the stone in question. This is the end point of the exercise, to identify an unknown material in terms of its mineralogical group, species and variety.
How To Identify Lechleitner Synthetic Ruby
The veteran Austrian crystal grower Johann Lechleitner is the genius behind the production of synthetic corundum in a variety of colors by the flux process. The experimentation began in 1983. As with Knischka, Lechleitner uses seeds as a focus for growth. His production can be divided into two types depending on the type of seed used.
- Type 1
Growth on Verneuil seeds. These are grown in a variety of colors (red, pink, orange, blue, yellow, green and colorless) with the color of the seed usually matching that of the overgrowth. Inclusions are characteristic of both the flux method of growth (reminiscent of Kashan and Chatham synthetics) and of the Verneuil seed (gas bubbles, curved striae and color banding). This is a characteristic and easily recognized assemblage of inclusions.
- Type 2
Growth on natural corundum seeds. This type of Lechleitner synthetic requires much closer attention. The synthetic overgrowth will adopt the crystal habit of the seed underneath and reproduce growth structures identical to the natural material (i.e. an overgrowth on a Thai ruby seed will produce a tabular crystal of identical habit to the natural crystal). Repeated twinning found in the seed will continue out into the overgrowth.
Inclusions in the seed portion can easily confuse the eye, especially if the identification is hasty. Features typical of flux-growth corundums should be seen in the overgrowth. The best method of detecting type 2 corundums would seem to be with immersion in high RI liquid, but even with this technique it may be difficult to see the boundary between the seed and the overgrowth (this should be present as a narrow colorless layer at the junction). Unfortunately, the growth process seems to use such high temperatures that the surface of the seed may be actively dissolved by the flux, making the junction between seed and overgrowth harder to detect.
The cutting process may also remove much of the overgrowth, in which case the inclusions within the seed would be more noticeable than the flux inclusions left in the vestiges of the seed. One consequence of using a natural seed will be the difference in fluorescence between the two 'components' of the stone. Under longwave ultraviolet light the natural seed will glow a much weaker red than the overgrowth, which will fluoresce bright red.
The stones are rare. You may find the specimens only at a few gemological schools, gem research laboratories and among private collectors.
- Type 1
Growth on Verneuil seeds. These are grown in a variety of colors (red, pink, orange, blue, yellow, green and colorless) with the color of the seed usually matching that of the overgrowth. Inclusions are characteristic of both the flux method of growth (reminiscent of Kashan and Chatham synthetics) and of the Verneuil seed (gas bubbles, curved striae and color banding). This is a characteristic and easily recognized assemblage of inclusions.
- Type 2
Growth on natural corundum seeds. This type of Lechleitner synthetic requires much closer attention. The synthetic overgrowth will adopt the crystal habit of the seed underneath and reproduce growth structures identical to the natural material (i.e. an overgrowth on a Thai ruby seed will produce a tabular crystal of identical habit to the natural crystal). Repeated twinning found in the seed will continue out into the overgrowth.
Inclusions in the seed portion can easily confuse the eye, especially if the identification is hasty. Features typical of flux-growth corundums should be seen in the overgrowth. The best method of detecting type 2 corundums would seem to be with immersion in high RI liquid, but even with this technique it may be difficult to see the boundary between the seed and the overgrowth (this should be present as a narrow colorless layer at the junction). Unfortunately, the growth process seems to use such high temperatures that the surface of the seed may be actively dissolved by the flux, making the junction between seed and overgrowth harder to detect.
The cutting process may also remove much of the overgrowth, in which case the inclusions within the seed would be more noticeable than the flux inclusions left in the vestiges of the seed. One consequence of using a natural seed will be the difference in fluorescence between the two 'components' of the stone. Under longwave ultraviolet light the natural seed will glow a much weaker red than the overgrowth, which will fluoresce bright red.
The stones are rare. You may find the specimens only at a few gemological schools, gem research laboratories and among private collectors.
Monday, June 25, 2007
China's Gemstone Market Booms
Chen Nan Yang writes about the total size of the jewelry, colored stones including jade market @ http://www.colored-stone.com/stories/mar07/china.cfm
The Naked Face
Malcolm Gladwell writes about reading people's thought by looking at them + Paul Ekman's techniques + Facial Action Coding System @ http://www.gladwell.com/2002/2002_08_05_a_face.htm
The concept might be useful in the gem and jewelry trade where you meet ninety five five's (ninety five percent bluffs + 5 percent truth) a lot + with Facial Action Coding System you may be able to weed out the crooks.
The concept might be useful in the gem and jewelry trade where you meet ninety five five's (ninety five percent bluffs + 5 percent truth) a lot + with Facial Action Coding System you may be able to weed out the crooks.
White Moonstone Simulant
Heat treatment causes some of the alumina to crystallize out as corundum, which causes a diffuse reflection effect in the form of a moonstone-like sheen. The imitation moonstone synthetic spinel features a mirror-like coating on the back of the cabochon. The schiller-like effect is caused by exsolution of excess alumina which produces multitudes of tiny needles and can even produce star phenomena. The material is rare.
Russia: In Search of a Future Without De Beers
Chaim Even-Zohar writes about the fate of Supplier of Choice + the Russian influence + Kremlin's control over the diamond business through federal agencies + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=26759
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