GGTL Laboratories

• Only the original gemmological expertise report, unabridged, bearing the signatures of two members of the GGTL Laboratories Switzerland laboratory, bearing of the hologram and corresponding exactly to its copy held by the GGTL Laboratories Switzerland laboratory, is valid.
• The validity of the indicated mass (as weight) extends to the second decimal; the third decimal, noted as index, indicates only a trend.
• For technical reasons, the colour of the illustration may not exactly match the colour of the sample analysed.
• In agreement with the "full disclosure" principle, we mention all the treatments we were able to reveal in the frame of our analytical protocol. When the aim of the analysis is specified on a report, the other mentions being a matter for the "full disclosure" principle are not necessarily indicated.
• The jewel report does not necessarily contain all the observations mentioned on classical gemmological reports as the already mounted gems cannot always be analysed with advanced methods and can then be subject to a careful microscopic examination only.
• As the grading of the clarity and colour of set diamonds is not carried out under standard observation conditions, the results will be given for information purposes only as “apparent clarity” and “apparent colour”.
• The analysis aimed at identifying any synthetic stones present in batches of natural "mêlé" gemstones is systematically carried out on the entire batch.
• Pour la gradation de la pureté et de la couleur de lots de diamants "mêlé", un prélèvement statistique peut être appliqué. Ce prélèvement est basé sur un échantillonnage aléatoire simple impliquant un résultat avec un intervalle de confiance de 95% et une marge d’erreur maximale de 3%.

• Diamond grading is based on the following scales, ratings and illustrations:

  Colour scale

  

  Clarity scale

  

  Cut scale

  

  Clarity characteristics

  

• The conclusions issued by GGTL Laboratories Switzerland are based on our analytical protocols, which take into account gemmological knowledge and techniques recognised in specialist publications and/or by similar laboratories at a given point in time. These conclusions cannot, under any circumstances, take into account developments in this knowledge. Consequently, the laboratory cannot be held liable for any invalidation of the conclusions issued by GGTL Laboratories Switzerland due to developments in the aforementioned techniques and knowledge.
• Conclusions issued by the GGTL Laboratories Switzerland laboratory attest to the naturality and the identification of treatments in the material at the time of the expertise report, they do not take into consideration any subsequent treatment that the material could undergo after the expertise. Thus, the findings and conclusions contained in this report are valid only as of the date of issuance.
• Disputing the conclusions reached by GGTL Laboratories Switzerland based on contradictory conclusions issued by another laboratory, which are allegedly based on techniques and knowledge not published in scientific literature and therefore not validated by the scientific community, or considered irrelevant by GGTL Laboratories Switzerland, are inadmissible.
• Data provided by a client concerning the physical characteristics (mass, dimensions, number, etc.) of one or more gemstones, which are not related to measurements and counts performed by GGTL Laboratories Switzerland, are indicated on reports as "indicated".
• With the exception of proven error and/or established serious negligence, the GGTL Laboratories Switzerland laboratory will formally decline, as far as the law permits, any responsibility for any damages in relation to the expertise or of any matter ensuing further to any use of the said expertise. The word "expertise" embraces all written conclusions (in any medium: paper, electronic, etc.) or verbally expressed by the GGTL Laboratories Switzerland laboratory.
• GGTL Laboratories Switzerland decline all responsibility in the event of any change in the appearance of a gemstone (colour, transparency, etc.) analysed using an advanced, non-destructive technique carried out as part of our protocols.
• The laboratory does not assume any responsibility regarding the long-term stability of the colour of any sample analysed.
• As a matter of principle, GGTL Laboratories Switzerland does not provide any indication of the geographical origin of treated gemstones.
• The geographical origin possibly proposed, at any step of the analytical protocol, is given as an information only, being the most likely geographical origin. The indicated deposit origin refers only to the similarities of the physical and chemical characteristics observed on the analysed sample(s) and the data generally available on deposit samples known at the time of the analysis. The GGTL Laboratories Switzerland laboratory considers that it is rarely scientifically and formally demonstrable that a gemstone comes from a given deposit.
• The species name possibly offered for biogenic materials is simply indicative, as the best probability. Its evocation refers only to similarities between the observed characteristics on the analysed material and the data currently available on similar material from known species at the time of the expertise. All responsibilities regarding the procedures and documents relating to the species protection (CITES, etc.) are to be incurred by the client.
• The expression "No clarity enhancement" characterizes an emerald that has not undergone any treatment with the aim of improving its clarity, or that has been cleaned after such a treatment and in which there may remain very small residues that cannot enhance the clarity of the gem when observed with naked eyes.
• The corundum's thermal treatment process involves de facto the diffusion of some chemical elements in the crystal lattice of the so-treated gemstones, occurring fortuitously or as a voluntarily act. Unless a well-known diffusion technique is identified, described and validated in gemmological literature, only the mention of the thermal treatment will be indicated in the report.

• Presence of vitreous substances issued from corundum heat treatment is designated according to the following alphanumeric code, adapted from LMHC.

  

• For some gemstones, some treatments may be undetectable or difficult to detect, using the scientific instruments and methods available at the time of the analysis. In such case, the terms "usually irradiated" or "usually irradiated and annealed" or "usually thermally treated" or “usually treated” are used in reference to the market situation when the treatment in question is commonly used. This does not imply that any treatment was performed on the analysed gemstone.
• When no treatment is known or published in scientific literature for a given gemstone, the report states "--".
• Unless obvious reshaping or repolishing are observed in non-nacreous or nacreous pearls, the usual surface description will not be mentioned in the report.
• Unless it is required by a legal entity, the GGTL Laboratories Switzerland laboratory is not bound to justify its methods, technical reasoning or any other means deemed opportune to reach its conclusions.
• Data relating to the analysis and conclusions of the report are kept indefinitely.
• None of the conclusions contained in an analysis report (of any type) issued by the GGTL Laboratories Switzerland laboratory represents either a guarantee or an appraisal of the analysed gemstone(s).
• The duplication, even partial, and sale of any document published by the GGTL Laboratories Switzerland laboratory is strictly forbidden, including the present restrictions.
• Only the French version of the present restrictions is binding.
• Any dispute or litigation related to the documents or services supplied by the GGTL Laboratories Switzerland laboratory will fall exclusively within the jurisdiction of the Republic and Canton of Geneva, Switzerland.
• The "GGTL Laboratories Switzerland" laboratory is a member of the group "GGTL Laboratories".

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