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| Thread | Views | Replies | Last Post | |
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Cempaka Diamonds Diamonds |
797 | 16 | polaris1028 03-09-2010 02:16 |
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A common aftersale Question... Jade |
399 | 12 | polaris1028 03-09-2010 02:16 |
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Classification of gems. Other Coloured Stones |
3142 | 7 | polaris1028 03-09-2010 02:15 |
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Gold prices Jewellery and Design |
456 | 8 | polaris1028 03-09-2010 02:14 |
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Chemical Composition of Ruby Rubies and Sapphires |
4733 | 4 | polaris1028 03-09-2010 02:07 |
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"Red Sapphires" Rubies and Sapphires |
808 | 13 | polaris1028 03-09-2010 02:01 |
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Absorption Spectra Other Coloured Stones |
515 | 8 | polaris1028 02-09-2010 02:17 |
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So-called aquamarine Gemstone Identification |
505 | 8 | polaris1028 02-09-2010 02:16 |
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New Sub Forums! Gemstone Identification |
666 | 4 | polaris1028 02-09-2010 02:16 |
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White Substitutions or Alte... Jewellery and Design |
274 | 4 | polaris1028 02-09-2010 02:15 |
The following paper studies the variability in the mass of a carob seed, and explores the history behind how it became to be used as the standard for stone weight.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1686184/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1686184/
Finally expose on glass filled rubies in the news!!
Apparently even lemon juice will eat away the glass on rubies...
http://www.msnbc.msn.com/id/34348821/ns/business-consumer_news/
Apparently even lemon juice will eat away the glass on rubies...
http://www.msnbc.msn.com/id/34348821/ns/business-consumer_news/
Please just read the following about the Wrenkin Ruby:http://www.ft.com/cms/s/0/6c76dffe-adec-11de-87e7-00144feabdc0.html
This is not gem quality, and good enough to only be a doorstop. India and Madagascar produces huge pieces of such things - I won't even pay 4 digits for these.
So those that keep emailing me about valuation of huge rubies, read it first before emailing me. And if you have been scammed, I feel sorry for you - next time research first, or bring it to a gem lab for a verbal appraisal before buying.
I assure you most gem labs will tell you in the face it is at best carving quality. I don't like mincing words: I tell you it is worthless.
http://www.shanland.org/index.php?option=com_content&view=article&id=2655:monghsu-gemland-predators-and-preys&catid=feature&Itemid=267Unusual material reportedly from the Batakundi area a remote valley in Pakistan controlled Kashmir not very far from the Nangimali ruby deposit.
They were in a pinkish purple colour, and I had the luxury of seeing a parcel of them in 2007 :)
They were in a pinkish purple colour, and I had the luxury of seeing a parcel of them in 2007 :)
Campbell Bridges, the discoverer of the stone Tsavorite, was murdered near his mine in Kenya.It is probably necessary to remind ourselves that though cultured pearls are produced by oysters in a natural environment, it was initiated artificially through human intervention.
And it is this intervention that allows mass production. What used to be prized gemstones are now available in reasonably large sizes (12mm and above, fresh water pearls) due to indiscriminate farming of pearl oysters by the chinese.
Are South Sea Pearls still that blemish free? Ecologically harvested no doubt, it is still a mass production run. And best, with genetically modified oysters, we can be producing huge pearls in a fraction of the time!
When will all these mass production insanity cease? What used to be prized are now so heavily commercialised that strings of gorgeous pearls today are stigmatised.
I wonder what CIBJO will do next with classification and nomenclature: cultured pearls from natural oysters, cultured pearls from genetically modified oysters?!
http://www.news.com.au/couriermail/story/0,27574,25892574-3102,00.html
And it is this intervention that allows mass production. What used to be prized gemstones are now available in reasonably large sizes (12mm and above, fresh water pearls) due to indiscriminate farming of pearl oysters by the chinese.
Are South Sea Pearls still that blemish free? Ecologically harvested no doubt, it is still a mass production run. And best, with genetically modified oysters, we can be producing huge pearls in a fraction of the time!
When will all these mass production insanity cease? What used to be prized are now so heavily commercialised that strings of gorgeous pearls today are stigmatised.
I wonder what CIBJO will do next with classification and nomenclature: cultured pearls from natural oysters, cultured pearls from genetically modified oysters?!
http://www.news.com.au/couriermail/story/0,27574,25892574-3102,00.html
New rubies reported as “Mozambique” appeared in the market in Bangkok and Chanthaburi. It seems that this new material is coming from an area near the famous Niassa National Park in Northern Mozambique.
Rubies reported from the Niassa region in Mozambique are available in Bangkok and Chanthaburi as unheated stones, but also either as flux heated or lead glass filled material. Unlike the Winza stones it seems that the low quality Niassa material is suitable for heat treatment either using the flux or lead glass technologies depending on the quality of the rough.
They are often dark in tone but some stones were a very attractive bright red and clean. Compared to the Winza rubies (which are sometimes mixed with Niassa rubies) Niassa rubies are often less transparent; probably due to their silk inclusions. Blue color zoning, a common feature in Winza material, was not noticed in the current Niassa samples.
Rubies reported from the Niassa region in Mozambique are available in Bangkok and Chanthaburi as unheated stones, but also either as flux heated or lead glass filled material. Unlike the Winza stones it seems that the low quality Niassa material is suitable for heat treatment either using the flux or lead glass technologies depending on the quality of the rough.
They are often dark in tone but some stones were a very attractive bright red and clean. Compared to the Winza rubies (which are sometimes mixed with Niassa rubies) Niassa rubies are often less transparent; probably due to their silk inclusions. Blue color zoning, a common feature in Winza material, was not noticed in the current Niassa samples.
Some latest findings from around the world:New outcrops of
- Colour change garnets discovered in Kenya rivalling the best in Madagascar in the best qualities. Sizes are largely limited to below 3 carats, the majority are sub-caraters. Gem quality materials are confined to the smaller sizes.
- Chinese rhodochosite. Gem quality/facetable grade rhodochrosite has been discovered in China. Perhaps a new take on the classic Sweet Home Mine?
- New Russian Demantoids with classic horse-tails. A new mine has started producing russian demantoids with the highly desired horse-tail inclusions.
Demantoids can be heat treated
Laboratory Approaches Towards Disclosure
In the beginning the labs would not make the heat-or-no-heat call because it was undetectable. As their databases grew and internal characteristics began revealing more clues, new assumptions were made. Below are some of the current approaches the major laboratories are taking.
- Gemological Institute of America (GIA) – Will not identify whether a demantoid garnet has been heat treated; will not determine origin on demantoid garnets
- American Gem Trade Association (AGTA) disclosure – Enhancements: Indications of heating. Gemstones of this type may be heated to improve their appearance. This treatment is not detectable using current technologies; such heating is generally stable under normal wearing conditions. AGTA is not giving country of origin
- American Gemological Laboratories (AGL) disclosure – AGL will make the heating call, and give country of origin
- “It is in the opinion of the Laboratory, based on the weight of evidence, that the origin of this material would be classified as Russian. It is the opinion of the Laboratory that this material has been subjected to a low to moderate heat enhancement process to produce a permanent and stable color.”
- Gübelin Gemmological Laboratories – Will denote the country of origin but not whether the material has been subjected to heat
- SSEF Swiss Gemmological Institute – Will state country of origin and whether there are indications of heat treatment
The labs that do report country of origin are not able to pinpoint specific mines at this time.
The recent steep price hike on the Rapaport Diamond Report by about 25% is causing the diamond trade to freeze over some what. In response Rapaport will release sort of a Bid price and Ask price reports.President Obama has renewed sanctions against Myanmar, dashing the hopes of jewelry organizations worldwide that united earlier this summer to urge Congress to consider lifting the U.S. ban on rubies imported from the country.
Gemmological Association of All Japan website has an article on lead-glass treatment of ruby with interesting pictures that give an idea of the remarkable clarity-enhancing effect of the treatment. One surprising feature of the research is the finding that treated rubies may gain up to around 10% in weight from being glass-filled. As one might expect, they advise against immersing glass-filled rubies in jewellery chemicals such as pickling solution.
The second page of the article shows pictures of how appalling the degree of fracture filling can be. After dissolving away the lead glass, the opaque heavily fractured ruby is left.
Ruby filled with lead-glass in various degrees is currently circulating heavily in the market and care should be taken when dealing with ruby.
PARIS - A CHINESE bidder Wednesday snapped up an 18th-century Qing Dynasty seal for $3.3 million (1.68 million euros) at a Paris auction held despite protests from Beijing.
The white jade imperial seal, which Beijing says was looted from the Summer Palace in 1860, was acquired by a Chinese national who refused to give his name, telling reporters he was acting on behalf of an art collector in France.
NAIROBI (Kenya) - TWO men pleaded guilty in a Kenyan court on Monday to illegally possessing 700 kilograms of elephant tusks in what was believed to be the largest seizure of illegal ivory in recent years, a Kenyan official said.
New York--EGL USA has discovered the first visual observational criteria for identifying high-pressure, high-temperature treated (HPHT) diamonds, the lab announced recently.
According to a press release, the indicator, the "fluorescence cage," is a specific luminous, intersecting pattern along the cut edges and vertices of facets on particular colored HPHT-treated Ia diamonds with less than strong fluorescence.
The effect can be seen with a fluorescence microscope, and early results indicate that the effect is the result of the movement of optically active impurities triggered by the HPHT process.
Dr. Inga Dobrinets of EGL USA, along with Professor Alexander Zaitsev of the College of Staten Island/CUNY, completed the research to identify the cage.
"The visual observation of a fluorescence cage appears to be the most reliable feature used so far for the reporting of HPHT treatment," Dobrinets said in a media release. "A significant advantage of the cage-based identification is its comprehensive fidelity and technical simplicity. While the 'cage effect' may not appear on all HPHT-treated stones when it is evident, a conclusive identification can be made on that basis alone."
EGL USA Director Mitch Jakubovic said that in the coming months, the lab plans to use this breakthrough to provide HPHT identification in a more efficient and cost-effective way.
"At EGL USA, we always combine the best in science and service. This discovery, particularly the observational aspect, is a key example of that," he said.
According to the release, EGL USA will continue to research the cage effect, with final findings set for inclusion in a formal paper.
Source: National Jeweler
According to a press release, the indicator, the "fluorescence cage," is a specific luminous, intersecting pattern along the cut edges and vertices of facets on particular colored HPHT-treated Ia diamonds with less than strong fluorescence.
The effect can be seen with a fluorescence microscope, and early results indicate that the effect is the result of the movement of optically active impurities triggered by the HPHT process.
Dr. Inga Dobrinets of EGL USA, along with Professor Alexander Zaitsev of the College of Staten Island/CUNY, completed the research to identify the cage.
"The visual observation of a fluorescence cage appears to be the most reliable feature used so far for the reporting of HPHT treatment," Dobrinets said in a media release. "A significant advantage of the cage-based identification is its comprehensive fidelity and technical simplicity. While the 'cage effect' may not appear on all HPHT-treated stones when it is evident, a conclusive identification can be made on that basis alone."
EGL USA Director Mitch Jakubovic said that in the coming months, the lab plans to use this breakthrough to provide HPHT identification in a more efficient and cost-effective way.
"At EGL USA, we always combine the best in science and service. This discovery, particularly the observational aspect, is a key example of that," he said.
According to the release, EGL USA will continue to research the cage effect, with final findings set for inclusion in a formal paper.
Source: National Jeweler
An interesting read about the latest gem intrigue: The Gem of Tanzania
Friends have returned from Myanmar and Thailand and have reported severe slow down in the gem trade. For all stones, except Jadeite-Jade. Chinese traders in Myanmar continue to bid by the millions of Euros for jadeite boulders when the rest of the world is in the throes of recession. Jade continues in its jaw-dropping surge in prices and is sure to set more world records with the rising of China. Soon, Jade will be dominating the price of rubies at the rate Jade gains popularity with the larger Eastern population. Surprisingly, even the West has caught up in Jadeite appreciation!
Prices and demand for burmese rubies and sapphires seemed to have cooled down some what after the US sanctions and financial crisis.
The price of Gold has also taken a beating, after emergent roots of recovery excited the world's economy back into a massive 5-week long exuberant rally. Whether this exuberance will last? Your guess is as good as mine - whatever it is, it does affect our gold prices!
Prices and demand for burmese rubies and sapphires seemed to have cooled down some what after the US sanctions and financial crisis.
The price of Gold has also taken a beating, after emergent roots of recovery excited the world's economy back into a massive 5-week long exuberant rally. Whether this exuberance will last? Your guess is as good as mine - whatever it is, it does affect our gold prices!
Gold is generally seen as a safe haven in times of political and economic chaos because it has no counter-party risk and the metal's value is independent of any sovereign power.Commodities headed for the biggest weekly advance in two months as a record decline in the dollar bolstered demand for raw materials as a hedge against inflation.
The dollar was headed for a record weekly drop after the Federal Reserve said it may buy $300 billion of government debt and more mortgage bonds, increasing the supply of dollars.
Gold has little intrinsic value; if it had never been coined its price would probably rest around the $250 per ounce of the late 1990s. However because of its history it is regarded as an inflation hedge and store of value, and that psychological association becomes tighter as inflation worsens and the gold price rises. Hence arguments about the irrationality of gold investment are wrong: in an inflation-prone environment belief in gold becomes self-reinforcing.
When we’re talking about topaz, imperial is a descriptive term for golden orangey-yellow hues, and precious is usually reserved for the more pink-red hues. However, these terms can, and often are, used interchangeably by gem dealers. Exceptional colors like these are only found near the town of Ouro Preto within in the state of Minas Gerais in Brazil.
New diamond grading courses are soon being offered by HRD Antwerp, in Hong Kong. The effort is in close cooperation with the Hong Kong Institute of Gemmology. Two intensive programmes - the Certified Diamond Grader course and the ‘Diamond Rough Sorting Basic’ course will be tutored by an experienced HRD Antwerp instructor. The Certified Diamond Grader course delivers training in the principles of diamond optics, grading, identification and imitation detection.It will also offer students with extensive hands-on experience with a microscope and a loupe. The loupe teaches students the basic methods to sort diamonds in the various categories.
Georges Brys, CEO of HRD Antwerp NV, said “ It gives me great pleasure to see HRD Antwerp’s education programmes being linked to the respected Hong Kong Institute of Gemmology. Both our organisations will benefit from this mutual cooperation.”
The Lab will promote this initiative at the HK International Jewellery Show, HK Convention & Exhibition Centre.
Collector's Universe is pulling out of diamond grading and gem testing.The gem testing side (AGL) will close, diamond grading (GCAL) will be reacquired by Don Palmieri's Palmieri Group
GCAL (Gem Certification & Appraisal Lab, founded by Don Palmieri) was acquired by Collectors Universe in 2005, AGL (American Gemological Laboratories, founded C.R. "Cap" Beesley in 1977) was acquired by Collectors Universe in 2006.
The uncertain outlook for revenues in the light of the economic crisis is blamed.
Author: Peter G. Read
Manufacturer: Butterworth-Heinemann
Number Of Pages: 358
Manufacturer: Butterworth-Heinemann
Number Of Pages: 358
Since Gemmology was published, readers have used it to gain an in-depth appreciation of the science of gemmology, its history, and practice. This third edition has been completely revised to cover the latest methods of gem enhancement and identification, as well as the latest test instruments and laboratory techniques. Gemmology serves as an invaluable reference guide for gemmologists, professionals, and students, and is an invaluable text for anyone in the gemmological profession. Also included are details of the Gemmological Associations Foundation Course together with advice on examination techniques.