I found the article on Chinese Rhinoceros horn carvings @ http://www.iht.com/articles/2008/04/18/arts/raahorn.php interesting because they are stylistically different through various periods influenced by changing scholarly tastes + the value factor = size + color + rarity + quality (signed by known and recognized carvers), just like paintings, jewelry and gemstones.
Useful links:
www.christies.com
www.sothebys.com
Showing posts with label ivory. Show all posts
Showing posts with label ivory. Show all posts
Monday, April 21, 2008
Wednesday, March 26, 2008
Siberian Ivory Trade
The Russian exports of mammoth ivory is up--thanks to global warming: The article Trade in mammoth ivory @ http://www.iht.com/articles/2008/03/25/europe/mammoth.php was educational + interesting + I think there will be always demand for ivory in Asia, for personal uses despite the international ban on ivory trade.
Saturday, August 25, 2007
Lines Of Retzius
Anders Adolf Retzius (Stockholm, Sweden) was the first to describe the beautiful markings on elephant ivory known as ‘lines of Retzius’; today gemologists describe it as 'engine-turned' pattern in ivory.
According to Robert Webster, they appear as ‘striae of different shades of cream proceeding in the arc of a circle and forming by their decussations (lines crossing to form overlapping ‘X’ patterns) minute curvilinear lozenge-shaped spaces which appear like an engine turning…..These ‘lines of Retzius’, as they are called, are seen only in ivory from the elephants, and are not apparent in ivory from the other animals….The engine turning (pattern of overlapping X’s) is not seen in the imitations, and provides a certain check on the piece being ivory. The lines of Retzius…are due to the dentine being permeated with fine thread-like canals filled with a brownish gelatinous substance, which in life conducts the nerve fibrils. These fine canals extend outward from the pulp (central nerve and blood vessel) cavity of the tusk in flattened spirals of opposite hands, and it is these dense pores with their gelatinous contents which give to ivory its beautiful polish and exceptional elasticity.’ (Webster, 1983, p. 590)
The experts believe the dentine portion of ivory is roughly 70% mineral matter (mostly calcium phosphate in the form of apatite) and 30% organic matter (collagen, a complex protein), while enamel is roughly 99% mineral matter (mostly apatite) and 1% organic matter, making it durable and hardnest substance produced by the body (human/animal). Elephant ivory from traditional sources + ivory from extinct elephant species such as the Mastodon and Mammoth + the teeth of hippopotamus, walrus, narwhal, sperm (or cachalot) whale, wild boar and wart hog may be used for jewelry and works of art.
According to Robert Webster, they appear as ‘striae of different shades of cream proceeding in the arc of a circle and forming by their decussations (lines crossing to form overlapping ‘X’ patterns) minute curvilinear lozenge-shaped spaces which appear like an engine turning…..These ‘lines of Retzius’, as they are called, are seen only in ivory from the elephants, and are not apparent in ivory from the other animals….The engine turning (pattern of overlapping X’s) is not seen in the imitations, and provides a certain check on the piece being ivory. The lines of Retzius…are due to the dentine being permeated with fine thread-like canals filled with a brownish gelatinous substance, which in life conducts the nerve fibrils. These fine canals extend outward from the pulp (central nerve and blood vessel) cavity of the tusk in flattened spirals of opposite hands, and it is these dense pores with their gelatinous contents which give to ivory its beautiful polish and exceptional elasticity.’ (Webster, 1983, p. 590)
The experts believe the dentine portion of ivory is roughly 70% mineral matter (mostly calcium phosphate in the form of apatite) and 30% organic matter (collagen, a complex protein), while enamel is roughly 99% mineral matter (mostly apatite) and 1% organic matter, making it durable and hardnest substance produced by the body (human/animal). Elephant ivory from traditional sources + ivory from extinct elephant species such as the Mastodon and Mammoth + the teeth of hippopotamus, walrus, narwhal, sperm (or cachalot) whale, wild boar and wart hog may be used for jewelry and works of art.
Friday, June 15, 2007
Deal Cut On Elephants And Ivory
Richard Black writes about the deal made by South African nations on the immediate future of the ivory trade @ http://news.bbc.co.uk/2/hi/science/nature/6751853.stm
Friday, May 11, 2007
Asian Markets Push Illegal Ivory
BBC News writes:
The illegal ivory trade is expanding, driven by East Asian crime syndicates, according to the wildlife trade monitoring network Traffic.
The syndicates gather ivory in Africa for export to East Asian countries. The biggest market is mainland China, though there is also significant trade to other countries such as Thailand and the Philippines, and to Hong Kong.
Traffic says there are 92 illegal ivory seizures per month, and the number of large hauls has doubled in a decade. Its report will be presented to next month's meeting of the Convention on International Trade in Endangered Species (Cites), where wildlife campaigners hope it will put pressure on governments whose countries are used by the traffickers.
"The relevant question is whether Cites is going to crack down or not, whether governments are going to show some political will," said Sue Lieberman, director of the global species programme at WWF which runs Traffic together with the World Conservation Union (IUCN).
"The Asian market is the key. It is thriving again in Thailand, and a lot of Chinese businesses have moved into Africa, for example timber companies, which means more ivory is coming out," she told the BBC News website.
Big hauls up
Traffic bases its report on an analysis of nearly 12,400 records of ivory seizures in 82 countries dating back to 1989 as part of the Elephant Trade Information System (Etis). It clearly identifies the Democratic Republic of Congo, Cameroon and Nigeria as the main sources of illegal ivory.
"With myriad conflicts, central Africa is currently haemorrhaging ivory," observed Tom Milliken, director of Traffic's Africa programme. "These three countries are major conduits for trafficking illegal ivory from the region to international markets, particularly in Asia."
The number of seizures fell between 1990 and 1995, but there has been a rising trend since then. The number of large hauls - above one tonne - has also risen, which Dr Lieberman believes "demonstrates greater sophistication, organisation and finance".
China is identified as the single biggest market, though Traffic says enforcement has improved markedly in the last five years. On the African side, the conservation group singles out Ethiopia for praise as a country which has effectively implemented an action plan drawn up by Cites four years ago, clamping down on its domestic ivory market.
More info @ http://news.bbc.co.uk/2/hi/science/nature/6644365.stm
The illegal ivory trade is expanding, driven by East Asian crime syndicates, according to the wildlife trade monitoring network Traffic.
The syndicates gather ivory in Africa for export to East Asian countries. The biggest market is mainland China, though there is also significant trade to other countries such as Thailand and the Philippines, and to Hong Kong.
Traffic says there are 92 illegal ivory seizures per month, and the number of large hauls has doubled in a decade. Its report will be presented to next month's meeting of the Convention on International Trade in Endangered Species (Cites), where wildlife campaigners hope it will put pressure on governments whose countries are used by the traffickers.
"The relevant question is whether Cites is going to crack down or not, whether governments are going to show some political will," said Sue Lieberman, director of the global species programme at WWF which runs Traffic together with the World Conservation Union (IUCN).
"The Asian market is the key. It is thriving again in Thailand, and a lot of Chinese businesses have moved into Africa, for example timber companies, which means more ivory is coming out," she told the BBC News website.
Big hauls up
Traffic bases its report on an analysis of nearly 12,400 records of ivory seizures in 82 countries dating back to 1989 as part of the Elephant Trade Information System (Etis). It clearly identifies the Democratic Republic of Congo, Cameroon and Nigeria as the main sources of illegal ivory.
"With myriad conflicts, central Africa is currently haemorrhaging ivory," observed Tom Milliken, director of Traffic's Africa programme. "These three countries are major conduits for trafficking illegal ivory from the region to international markets, particularly in Asia."
The number of seizures fell between 1990 and 1995, but there has been a rising trend since then. The number of large hauls - above one tonne - has also risen, which Dr Lieberman believes "demonstrates greater sophistication, organisation and finance".
China is identified as the single biggest market, though Traffic says enforcement has improved markedly in the last five years. On the African side, the conservation group singles out Ethiopia for praise as a country which has effectively implemented an action plan drawn up by Cites four years ago, clamping down on its domestic ivory market.
More info @ http://news.bbc.co.uk/2/hi/science/nature/6644365.stm
Friday, March 16, 2007
An Alternative African Source Of Vegetable Ivory
(Wahroongai News, Volume 30, No.7, July 1996) Grahame Brown writes:
Vegetable ivory, a long used effective imitation for elephant ivory, is derived from the dried nuts of several species of palm tree. The common commercial source of vegetable ivory is the Corozo or Tagua palm (Phytelephas macrocarpa) from Central America and northern South America. This ivory colored vegetable material (nut) has a hardness of 2½, a specific gravity of 1.40 – 1.43, a spot refractive index of 1.54, and in hand specimen displays the polygonal outlines of its component plant cells.
Another source of African vegetable ivory was suggested by Webster to be the Doum or Gingerbread palm (Hyphaene thebaica) of north and central Africa. According to the 5th edition of Webster’s Gems, the rounded nuts of this palm have a reddish brown skin, and edible underlying spongy layer which is commonly converted into an alcoholic beverage, and a hard inner seed (the source of vegetable ivory).
A recent purchased guide, The Shell Field Guide to the Common Trees of the Okavango Delta and the Moremi Game Reserve, by Veronica Roodt, has provided some additional details about the African source of vegetable ivory.
According to Dr Roodt, the source of vegetable ivory in the Okavango Delta—a wildlife and vegetation-rich area of 18000 km² that is the terminus of the Cubango River in Botswana—is the Real Fan Palm (Hyphanae petersania). This majestic tree grows to a height of 20m, and has a bare stem crowned by arched fan-shaped green leaves.
The tennis ball sized fruits of this palm take 2 years to mature, and up to 2 years to fall. Consequently, this palm is decorated with fruit throughout the year. The nuts of the Real Fan Palm yield a whitish milk, that resembles and tastes like coconut milk, once the hard exocarp of the nut has been fractured. The external pulp of the nut is edible, and tastes like gingerbread. It may be fermented into a very potent palm wine. The hard, hollow internal endosperm of the nut is the source of vegetable ivory.
Elephants play a major role in the dispersion of the seeds of this palm, for elephants love the taste of these nuts. The endosperm (vegetable ivory) passes through the elephant’s digestive tract unscathed and may be collected from the animal’s faeces (as large brownish furry tennis balls). If the nuts are not harvested, the faeces act as a natural fertilizer to hasten the germination of seeds.
So, there you have it; an African source of vegetable ivory confirmed, and correctly assigned to source.
Vegetable ivory, a long used effective imitation for elephant ivory, is derived from the dried nuts of several species of palm tree. The common commercial source of vegetable ivory is the Corozo or Tagua palm (Phytelephas macrocarpa) from Central America and northern South America. This ivory colored vegetable material (nut) has a hardness of 2½, a specific gravity of 1.40 – 1.43, a spot refractive index of 1.54, and in hand specimen displays the polygonal outlines of its component plant cells.
Another source of African vegetable ivory was suggested by Webster to be the Doum or Gingerbread palm (Hyphaene thebaica) of north and central Africa. According to the 5th edition of Webster’s Gems, the rounded nuts of this palm have a reddish brown skin, and edible underlying spongy layer which is commonly converted into an alcoholic beverage, and a hard inner seed (the source of vegetable ivory).
A recent purchased guide, The Shell Field Guide to the Common Trees of the Okavango Delta and the Moremi Game Reserve, by Veronica Roodt, has provided some additional details about the African source of vegetable ivory.
According to Dr Roodt, the source of vegetable ivory in the Okavango Delta—a wildlife and vegetation-rich area of 18000 km² that is the terminus of the Cubango River in Botswana—is the Real Fan Palm (Hyphanae petersania). This majestic tree grows to a height of 20m, and has a bare stem crowned by arched fan-shaped green leaves.
The tennis ball sized fruits of this palm take 2 years to mature, and up to 2 years to fall. Consequently, this palm is decorated with fruit throughout the year. The nuts of the Real Fan Palm yield a whitish milk, that resembles and tastes like coconut milk, once the hard exocarp of the nut has been fractured. The external pulp of the nut is edible, and tastes like gingerbread. It may be fermented into a very potent palm wine. The hard, hollow internal endosperm of the nut is the source of vegetable ivory.
Elephants play a major role in the dispersion of the seeds of this palm, for elephants love the taste of these nuts. The endosperm (vegetable ivory) passes through the elephant’s digestive tract unscathed and may be collected from the animal’s faeces (as large brownish furry tennis balls). If the nuts are not harvested, the faeces act as a natural fertilizer to hasten the germination of seeds.
So, there you have it; an African source of vegetable ivory confirmed, and correctly assigned to source.
Wednesday, March 07, 2007
DNA Tracking
Read on how seal penises, elephant dung and smashed ivory are helping geneticists pinpoint the poaching of protected species @ http://www.economist.com/science/displaystory.cfm?story_id=8770177
Thursday, February 01, 2007
How To Identify The Source Of African Ivory
Using sophisticated statistical analysis of genetic data the scientists are applying new DNA techniques extracted from African elephant dung and skin samples to identify the origin of illegally poached ivory with remarkable accuracy.
More info @ http://www.abc.net.au/science/news/stories/s1208970.htm
More info @ http://www.abc.net.au/science/news/stories/s1208970.htm
Thursday, December 28, 2006
Steller's Sea Cow Bone
(via) Gemmology Queensland writes:
A rare ivory look-alike
Steller's sea cow (hydrodamalis gigas) is an extinct ancestor of the dugong that did not survive the 18th century. The first Steller's sea cows were discovered by Danish Captain Vitus Bering who was commisioned by Tsar Peter I (Peter the Great) to determine whether or not Asia and the Americas were one or two separate continents. One a second expedition in 1741, to map the area between Asia and North America, Bering was accompanied by a German doctor-naturalist named Georg Wilhem Steller. During this expedition, the ship ran aground and before his colleagues escaped, by building a new boat out of the timbers of the wrecked vessel. Steller, who died on what is now known as Bering Island, catalogued numerous species of plants and animals, some of which are named after him.
One such marine animal was a large sea cow that is now known as Steller's sea cow. This herbiverous marine mammal was twice the size of the presently living dugong. It had a length of 8.5m, a girth of 6.7m, and weighed up to 3628kg (8000 pounds0. It had no teeth, but its bones were massive. At the time of their discovery it is likely that from 1500-2000 Steller's sea cow were in existence. Due to the delicacy of their meat, by 1768 the last sea cow had been killed, with Stellar dying only four years after the expedition, never knowing of the extinction of the animal that bore his name.
Since the 1800s, there have been reported sightings of small colonies of Steller's sea cows in remote areas away from Russian fishing grounds and boat traffic. The few intact skeletons of Steller's sea cow that still exist can be found in a few museums that are scattered around the world. Today, the skeletal remains of this now extinct sea cow are recovered by indegenous natives from both sides of the Bering Strait, and these bones are either being sold as rough or are carved into some attractive ivory-like objects, such as knife handles--usually after they have been impregnated with a colorless synthetic polymer. The raw material, which seems to be predominantly derived from the large ribs of this now extinct animal, has a grayish to brownish color, is relatively porous, and has a core of or porous cacellous bone and an outer layer of thick cortical bone. This is rare, but very interesting material that could be misidentified as ivory.
A rare ivory look-alike
Steller's sea cow (hydrodamalis gigas) is an extinct ancestor of the dugong that did not survive the 18th century. The first Steller's sea cows were discovered by Danish Captain Vitus Bering who was commisioned by Tsar Peter I (Peter the Great) to determine whether or not Asia and the Americas were one or two separate continents. One a second expedition in 1741, to map the area between Asia and North America, Bering was accompanied by a German doctor-naturalist named Georg Wilhem Steller. During this expedition, the ship ran aground and before his colleagues escaped, by building a new boat out of the timbers of the wrecked vessel. Steller, who died on what is now known as Bering Island, catalogued numerous species of plants and animals, some of which are named after him.
One such marine animal was a large sea cow that is now known as Steller's sea cow. This herbiverous marine mammal was twice the size of the presently living dugong. It had a length of 8.5m, a girth of 6.7m, and weighed up to 3628kg (8000 pounds0. It had no teeth, but its bones were massive. At the time of their discovery it is likely that from 1500-2000 Steller's sea cow were in existence. Due to the delicacy of their meat, by 1768 the last sea cow had been killed, with Stellar dying only four years after the expedition, never knowing of the extinction of the animal that bore his name.
Since the 1800s, there have been reported sightings of small colonies of Steller's sea cows in remote areas away from Russian fishing grounds and boat traffic. The few intact skeletons of Steller's sea cow that still exist can be found in a few museums that are scattered around the world. Today, the skeletal remains of this now extinct sea cow are recovered by indegenous natives from both sides of the Bering Strait, and these bones are either being sold as rough or are carved into some attractive ivory-like objects, such as knife handles--usually after they have been impregnated with a colorless synthetic polymer. The raw material, which seems to be predominantly derived from the large ribs of this now extinct animal, has a grayish to brownish color, is relatively porous, and has a core of or porous cacellous bone and an outer layer of thick cortical bone. This is rare, but very interesting material that could be misidentified as ivory.
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