Wednesday, June 27, 2007
Liberian Diamonds
The European Union has lifted its embargo on Liberian diamonds, after the UN Security Council became satisfied that the trade in the so-called blood diamonds had been stemmed.
What Is The First Known Piece Of Gold Jewelry?
(via Commodity Online) Rediff writes:
The earliest gold jewelry dates from the Sumer civilization in between the Tigris and Euphrates rivers in southern Iraq around 3,000 BC. A major archeological find of early jewelry was in the Royal tombs of Ur, in Mesopotamia, dated to around 2,600 BC where gold articles made by lost wax casting included a wild ass on the rein ring of a chariot. Copper and bronze inlaid with gold also date to this period, demonstrating the craft skills in metalworking that existed. A beautifully modeled bull cast in gold dating to 2,300 BC was found in the Caucasus in Eastern Europe. In Egypt, gold jewelry and other artifacts have been found in Pharoah's tombs dating to around 1500 BC and later.
The earliest gold jewelry dates from the Sumer civilization in between the Tigris and Euphrates rivers in southern Iraq around 3,000 BC. A major archeological find of early jewelry was in the Royal tombs of Ur, in Mesopotamia, dated to around 2,600 BC where gold articles made by lost wax casting included a wild ass on the rein ring of a chariot. Copper and bronze inlaid with gold also date to this period, demonstrating the craft skills in metalworking that existed. A beautifully modeled bull cast in gold dating to 2,300 BC was found in the Caucasus in Eastern Europe. In Egypt, gold jewelry and other artifacts have been found in Pharoah's tombs dating to around 1500 BC and later.
Looking Back At the Future
Chaim Even-Zohar writes about the lack of liquidity in the diamond industry, bankruptcies, lack of success in the development and financing of branded diamonds + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=26653
How To Identify Lechleitner Synthetic Hydrothermal Emerald
Lechleitner emerald-coated beryl (Emerita - first marketed in 1960 by Austrian Johann Lechleitner in 1960, Austria). Produced hydrothermally by growing a coating of synthetic emerald over an already faceted specimen of natural colorless or pale colored beryl.
Detection
- Crazed effect in overcoat layer with cracks intersecting at 90°.
- Generally poor polish (repolishing may cause bald patches); some small back facets left unpolished to enhance depth of color.
- Dark rim of overgrowth area (best seen when stone immersed methylene iodide).
- Overgrowth area may fluoresce (weak to moderate red (LW & SW).
- Depending on the type of beryl used for the core (e.g., pale pink beryl or aquamarine), S.G. and inclusions noted might be wrong for emerald.
Lechleitner sandwich
Composite of natural or synthetic colorless beryl with overgrowth of dark green synthetic emerald. The sandwich type was first produced in 1964. Seed plate is of natural or synthetic beryl upon which a plate of emerald is grown. This may be subsequently enlarged by growing on synthetic colorless beryl. Multiple sandwiches have also been produced.
Detection
-Magnification: typical hydrothermal inclusions (and physical constants)
- Structure is only exhibited when viewed from the side or when immersed in a suitable liquid.
- Nail-like growth tubes may be seen streaming away from the seed crystal.
Lechleitner types
- Type 1
Thin hydrothermal synthetic emerald skin grown on a faceted natural colorless beryl seed. The skin displays a characteristic checkerboard-like appearance of narrow cracks. Thickness of the overgrowth varies from one facet to another, resulting in obvious differences in the depth of color on different facets. Natural inclusions may be found in the seed.
- Type 2
Sandwich-like consisting of a thin slice of natural colorless beryl surrounded by hydrothermal synthetic emerald. The colorless seed generally is found at the girdle and runs parallel to the table. Inclusions are the same as in type 3 & 4.
- Type 3 & 4
Full hydrothermal synthetic, featuring nails-like, unidentified tiny black and red specks, straight color zoning, etc.
The stones are rare. They are found only in a few gemological schools and gem research laboratories for study purposes.
Detection
- Crazed effect in overcoat layer with cracks intersecting at 90°.
- Generally poor polish (repolishing may cause bald patches); some small back facets left unpolished to enhance depth of color.
- Dark rim of overgrowth area (best seen when stone immersed methylene iodide).
- Overgrowth area may fluoresce (weak to moderate red (LW & SW).
- Depending on the type of beryl used for the core (e.g., pale pink beryl or aquamarine), S.G. and inclusions noted might be wrong for emerald.
Lechleitner sandwich
Composite of natural or synthetic colorless beryl with overgrowth of dark green synthetic emerald. The sandwich type was first produced in 1964. Seed plate is of natural or synthetic beryl upon which a plate of emerald is grown. This may be subsequently enlarged by growing on synthetic colorless beryl. Multiple sandwiches have also been produced.
Detection
-Magnification: typical hydrothermal inclusions (and physical constants)
- Structure is only exhibited when viewed from the side or when immersed in a suitable liquid.
- Nail-like growth tubes may be seen streaming away from the seed crystal.
Lechleitner types
- Type 1
Thin hydrothermal synthetic emerald skin grown on a faceted natural colorless beryl seed. The skin displays a characteristic checkerboard-like appearance of narrow cracks. Thickness of the overgrowth varies from one facet to another, resulting in obvious differences in the depth of color on different facets. Natural inclusions may be found in the seed.
- Type 2
Sandwich-like consisting of a thin slice of natural colorless beryl surrounded by hydrothermal synthetic emerald. The colorless seed generally is found at the girdle and runs parallel to the table. Inclusions are the same as in type 3 & 4.
- Type 3 & 4
Full hydrothermal synthetic, featuring nails-like, unidentified tiny black and red specks, straight color zoning, etc.
The stones are rare. They are found only in a few gemological schools and gem research laboratories for study purposes.
Tuesday, June 26, 2007
Jewelry Information Center Launches Vlogs
The Jewelry Information Center (JIC) has launched a series of video blogs (vlogs) on its website www.jic.org to reach out to manufacturing and retail members + educate consumers in a simple format.
Which Are The Famous Films About Gold?
- Goldfinger
- The Italian Job
- The Maltese Falcon
- The Lavender Hill Mob.
- The Italian Job
- The Maltese Falcon
- The Lavender Hill Mob.
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.
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