We all know the image from film and television: a jeweler leaning over a diamond, a ring, or a necklace with a loupe and tweezers, humming contentedly (or perhaps not) and declaring the carat, cut, quality, and value of the inspected piece with firm conviction. As beautiful as this scene may be, it is unfortunately quite misleading. For while a quick glance through a loupe can at most provide a preliminary assessment of a stone, a true analysis is significantly more complex. But why…?
Quite simply: a diamond cannot be 100% classified while it is set
The type of setting, the color of the precious metal used, and even the reflecting facets distract from the actual inclusions and color of the diamond—and logically, its actual size can only be estimated. Therefore, for a serious assessment, it must be removed from the setting and examined through a microscope with incident and transmitted light. In the process, it is embedded in a special fluid, which reduces any reflections and makes the analysis even more precise.
Certificate
A diamond certificate is a written confirmation of a diamond's quality, based on the 4Cs (Carat, Cut, Color, Clarity). However, it does not contain a price and serves merely as a recommendation. Such a certificate can be issued by any jeweler or goldsmith. By contrast, an appraisal (Gutachten) generally refers to a more comprehensive evaluation and can also include the value of the diamond. An expert report (Expertise), on the other hand, goes even further by providing a detailed analysis of the diamond's characteristics, often by an independent and specialized gemologist. Therefore, certificates, appraisals, and expert reports differ in their scope and the depth of the diamond's assessment.
Diamond Expert Report
An expert report (Expertise) is also often called an appraisal or report. The difference between an expert report and a certificate lies in the person or entity issuing it: expert reports may only be issued by a laboratory, an association of appraisers, or a generally sworn and court-certified expert! This eliminates the aspect of "subjectivity" in the assessment described for certificates, which is why expert reports can and should also provide clear price estimates.
Finally, one should note when an appraisal or certificate was issued, because the applicable classification of a diamond's cut changed in 2009/10.
And if you are dealing with loose stones (which, for example, are yet to be set into a piece of jewelry), it is important to note which institute categorized the stone (and according to which guidelines). Examples of renowned institutes include: GIA – Gemological Institute of America, IDC – International Diamond Council, IGI – International Gemological Institute, ÖGEM – Austrian Gemmological Society, SSEF – Swiss Gemmological Institute.
