HomeMajor Colored StonesRubies and SapphiresOrigin Determination of Rubies and Sapphires
Geographical origin determination of a gemstone does not indicate quality or value of the gemstone and should be regarded as an opinion proposed by the gemmological laboratory that identifies its origin. CIBJO regulations also have this philosophy as its basic principle. On the other hand, origin determination of a gemstone sometimes poses importance archeologically, and is one of information that jewellers are anxious for in their daily trades. Different origin determination on a single stone by different laboratories will bring on confusion among customers, and this may eventually reduce trust in laboratories. Therefore, origin determination should be made on more sophisticated scientific basis.

Origin determination of a gemstone has focused mainly on observation of internal features. Spectroscopic analysis and measurement of impurity elements by X-ray fluorescence provide us important clues in searching for origin determination of a gemstone. With these methods, determination of occurrence, that is, distinction between basaltic origin (for instance, from Australia, China or Thailand) and non-basaltic origin (from Sri Lanka, Myanmar or Madagascar for instance), are easy. However, distinction between origins within the similar occurrence, such as between Thailand and Australia, or Madagascar and Sri Lanka, are difficult. Especially after late 1990ユs when blue sapphires from Madagascar came into fashion in the gem market, distinction between blue sapphires from Madagascar, where is rather new origin, and those from Sri Lanka, where is a traditional origin, often raises problem in the industry. 

Here are all the articles and research papers that we can find on the internet on the Origin Determination of Ruby and Sapphire.
 
You are most welcome to share with us links that you feel should be here. Just drop a comment in the comment box.



For the Trade

A report, with the right origin is a strong sales argument. Especially auction houses and high-end jewellers prefer to sell their gemstones with such reports. Colombian emeralds, Burmese rubies and sapphires, or Kashmir sapphires are among the most beautiful and most wanted and therefore obtain much higher prices than their counterparts from other countries. (Lore Kiefert, New York, NY, USA, GemmoBasel 2005)

Accuracy and Limitation of Geographic Origin Determination

Gem identification report is commonly known as a means to express properties and features of gemstones set in jewellery. On the reports, gemmological properties possessed by each gemstone are described, including its natural or synthetic origin as well as mineral species, variety name and possible artificial treatment on the gemstone. As an option on customer’s request, determination of geographical origin of the gemstone so called “Origin Determination” may be made. To achieve accurate identification on these subjects, more sophisticated analytical instruments are required if necessary as well as standard gemmological identification technique. Also, to improve the precision of identification results, knowledge and experienced accumulated for long years, massive database possessed by the lab and a criterion for consistency are required. Particularly, origin determination of a gemstone has to restrict the geographical area from where each gemstone has occurred, so that it needs background of a gemstone to determine geological environment and global tectonics from which the gemstone has been derived. To meet the requirement, collecting specimens of clearly known locality is essential, and the abundant specimens must be reliably divided by each locality. The detailed internal observation and standard gemmological properties must be obtained first to create a database. In addition, UV-Visible spectrophotometry, infrared spectrophotometry (FTIR), Raman micro spectrometry analysis, fluorescent X-ray analysis and eventually analysis on trace and ultra-trace elements by LA- ICP-MS are operated to identify them by specialists who have knowledge and experiences on crystal growth of minerals, formation of rocks and plate tectonics.
 
It must be noted that the result of origin determination must be regarded as an opinion of a laboratory that investigated a particular gemstone, and it is not what to be proved, and so that the described origin never indicates any quality and value of the gemstone. The origin results is drawn from comparison with massive specimens with known localities and with database, from results of continuous research to date and from reference information, and the most possible origin of the gemstone tested is described on a report. There is rarely a case that some origins of a certain gem variety show quite similar properties and specific origin cannot be determined. There is also possibility that description of new origin with less information at early stage may cause time-lag.

Geographical origin determination of a gemstone does not indicate quality or value of the gemstone and should be regarded as an opinion proposed by the gemmological laboratory that identifies its origin. CIBJO regulations also have this philosophy as its basic principle. On the other hand, origin determination of a gemstone sometimes poses importance archeologically, and is one of information that jewellers are anxious for in their daily trades. Different origin determination on a single stone by different laboratories will bring on confusion among customers, and this may eventually reduce trust in laboratories. Therefore, origin determination should be made on more sophisticated scientific basis.

Despite the difficulties, labs such as AGL, SSEF, and the American Gem Trade Association Gemological Testing Center say they can issue country of origin opinions on the majority of the sapphires they are asked to evaluate.

It is of little commercial interest to know the locality of basaltic deposits, as in Rwanda, Australia, Cambodia, Thailand, Shandong [China], etc., . We are speaking of Kashmir, Burma, and Ceylon/ Madagascar / Tunduru where probably 80 percent are positive attributions. (Hanni, Ganoksin interview)

Because determining country of origin for a stone relies more on expert opinion than on conclusive evidence, labs will differ occasionally. They will also sometimes find it necessary to issue a "tentative" opinion, or no opinion at all.

For that reason, some labs do not offer origin reports on any stone. The Gemological Institute of America is one, and Professional Gem Sciences is another. (Source: http://www.ganoksin.com/borisat/nenam/cs-sapphire-origin.htm)

Sources:
http://www.gaaj-zenhokyo.co.jp/researchroom/2005/2005_09b-01e.html
http://www.gaaj-zenhokyo.co.jp/researchroom/kanbetu/2004/kan_2004_06-01en.html 

Techniques
Detailed chemical analysis and measurement of physical properties
Although most sapphires will show the same basic composition, the strength of the concentrations of trace elements can indicate which deposit the sapphire came from. Determination of the authenticity and country of origin of a gemstone is based on the testing of the chemical and physical properties of the gemstone under investigation by Spectroscopic analysis and measurement of impurity elements by X-ray fluorescence provide us important clues in searching for origin determination of a gemstone. With these methods, determination of occurrence, that is, distinction between basaltic origin (for instance, from Australia, China or Thailand) and non-basaltic origin (from Sri Lanka, Myanmar or Madagascar for instance), are easy. However, distinction between origins within the similar occurrence, such as between Thailand and Australia, or Madagascar and Sri Lanka, are difficult. Especially after late 1990s when blue sapphires from Madagascar came into fashion in the gem market, distinction between blue sapphires from Madagascar, where is rather new origin, and those from Sri Lanka, where is a traditional origin, often raises problem in the industry.
 
Cambodian sapphires, many of which are often touted as Kashmir "lookalikes," often show very high concentrations of iron, while Kashmir sapphires typically have very low iron levels(Beesley). Absorption spectra produced by these technologies make such differences readily apparent even when the stones are visually quite similar. Source: http://www.ganoksin.com/borisat/nenam/cs-sapphire-origin.htm

Oxygen Isotopes for Origin Determination
Gaston Giuliani, Vandoeuvre-les-Nancy, France, GemmoBasel 2005
 
Internal Characteristics
Origin determination of a gemstone has focused mainly on observation of internal features e.g. inclusions and growth structures using standard gemmological instruments and modern analytical instruments including spectrometers.
 
Growth Characteristics
Tight optical growth patterns are found regularly in Madagascan sapphires, less regularly in Sri Lankan and Myanmar stones, and not at all in Kashmir sapphire.(Beesley)

Colour zoning can also indicate the sapphire's origin. Sapphire crystals from Antsiranana Province in Madagascar, for example, often display blue violet, greenish blue, and greenish yellow zones within the same crystal. Kashmir sapphires exhibit sharp-bordered zones of blue and milky white. Source: http://www.ganoksin.com/borisat/nenam/cs-sapphire-origin.htm

Results
The conclusion on the country of origin, authenticity, and treatment of gemstones is an opinion of the laboratory based on the direct comparison of the findings with those obtained from the analyses of reference materials, as well as those in published literature. This knowledge is continuously updated by the laboratory to the extent reasonably possible.

In order to render an opinion on the probable origin of a sapphire, gemmologists look at a number of characteristics, like inclusions in the stone, growth structures, and chemical composition.

Conclusions will be based on all these factors, not on any single one.

The greater the number of individual and characteristic properties found in a certain stone, the more reliable is a determination of origin.

Sources:
http://www.gaaj-zenhokyo.co.jp/researchroom/2005/2005_09b-01e.html
http://www.gaaj-zenhokyo.co.jp/researchroom/kanbetu/2004/kan_2004_06-01en.html
http://www.gemresearch.ch/origin.htm
http://www.ganoksin.com/borisat/nenam/cs-sapphire-origin.htm

Madagascan, Tanzanian and Sri Lankan Sapphires
Similarities in chemical composition of sapphires of the three places are due to the geological setting during their formation. The Pan-African Belt crossed through the Gondwana continent at the sitewhere Madagascar, Tanzania and Sri Lanka formed one single landmass. (Dissanayake & Chandrajith, 1999, Lore Kiefert at GemmoBasel 2005)

LA-ICP MS analyses on specimen samples by GAAJ revealed that almost the same amount of highly concentrated Ti and Fe were detected in blue sapphires from both Madagascar and Sri Lanka. Ti and Fe in the stones from Madagascar were 0.003%~0.012% and 0.088%~0.112%, and in the stones from Sri Lanka were 0.0008%~0.017% and 0.018%~0.113% respectively. Contented amount of Na, K, Cr or Ga tend to be slightly higher in the stone from Sri Lanka but no significant difference were recognised.

Minute amount of heavy elements such as Sn (tin) and Ta (tantalum) were under detection limit in the stones from Sri Lanka, while several to several dozens ppm of those elements were detected in the stones from Madagascar, which posed significant difference between them. Tables and charts can be found in their paper.
Source: http://www.gaaj-zenhokyo.co.jp/researchroom/kanbetu/2004/kan_2004_06-02en.html

Blue sapphires of non-basaltic origin from Madagascar and from Sri Lanka, which were difficult to be distinguished from each other by traditional methods such as observation of internal features, spectroscopic analytical method or trace-element analysis by X-ray fluorescence analytical method showed distinct differences. This means that Sn (tin) and Ta (tantalum) from Madagascar were detected in order of ppm, while those two elements were under detection limit in the stones from Sri Lanka.

GAAJ concluded that the analysis of trace elements by LA-ICP-MS provide us important information in studying growth environment of a gemstone. We would like to gain more samples to improve the sensitivity of origin determination.
Source: http://www.gaaj-zenhokyo.co.jp/researchroom/kanbetu/2004/kan_2004_06-02en.html

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