About the

"Laboratory Manual Harmonisation Committee"



Gemmological laboratories offer a wide range of services from gemstone and gemstone treatment identification to origin determinations and diamond grading. Their services include the identification of the nature of a particular gemstone, whether it is an unaltered gem formed in nature, a synthetic created by man or even an imitation. Gemmological laboratories can also determine if a gem is treated to improve its color or transparency and some can also provide information about the probable geographic origin of a gemstone.


Previously laboratories located in different continents and markets were using their own report wording and language to describe the results of their testing. Along with the globalisation of the industry and ease of consumer travel there became a need for greater harmony in the wording used in gemmological laboratory reports.


The Laboratory Manual Harmonisation Committee (LMHC) is comprised of representatives from the following gemmological laboratories located in Europe, USA and Asia (listed here in alphabetical order):


- the CGL Laboratory, located in Tokyo, Nagoya, Osaka, Fukuoka & Kofu in Japan.

- the CISGEM Laboratory, located in Milan, Italy.

- the DSEF German Gem Lab, located in Idar Oberstein, Germany.

- the GIA Laboratory with 3 locations: Two in the USA (Carlsbad and New York), one in Bangkok, Thailand.

- the GIT-Gem Testing Laboratory, located in Bangkok, Thailand.

- the Gübelin Gem Lab Ltd., located in Lucerne, Switzerland.

- the Swiss Gemmological Institute - SSEF, located in Basel, Switzerland.

While the LMHC was originally formed at the request of GILC, the LMHC is not formally connected to any trade organization. 
The LMHC draws on the individual experiences of its members for the purpose of creating a general philosophy for proper nomenclature and disclosure for laboratories as well as to initiate and suggest "preferable" language to be used in the trade.
The goal of the Laboratory Manual Harmonisation Committee is to achieve the harmonisation of gemmological report language and thereafter the revision of this harmonised report language as used by LMHC members.
The LMHC meets several times a year to update or add to the contents of a manual.
When they are relevant to the trade, parts of this manual are released in the form of Information Sheets.
The opinions or findings in these documents are based on the state of knowledge at the time of the latest publication and may change as new information becomes available.





GILC (the Gemstone Industry and Laboratory Committee) is a worldwide committee of industry organisations and gemmological laboratories that meets on an annual basis. These meetings acknowledge that there are areas of misunderstanding and confusion within the gemstone industry concerning nomenclature and disclosure issues as they relate to laboratory reports and work towards the elimination of this confusion.


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