In gemstone science, all visually recognizable irregularities inside the gemstones – such as material foreign bodies (minerals, liquids, gases), cracks, color zoning or twin lamellae – are understood as inclusions. Often they cannot be seen with the naked eye, but only with the help of a gemstone microscope. The type and shape of the inclusions often also allow conclusions to be drawn about which gemstones they are and from which outlets they originate.
In diamond valuation, the clarity grade FL/IF-VS (flawless to very small inclusions) determines the value, among other things.
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Gem microscope
427,00 €Microscope with incident and transmitted light, dark-field illumination (dark-field condenser), ideal for viewing outlines of low-contrast inclusions
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Immersion microscope zoom
2.298,00 €Powerful stereo microscope with a large zoom range and long working distance, enabling observations with high technical prerequisites
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Immersion microscope
1.487,00 €Horizontal microscope for investigations in immersion liquids, required when interfering reflections on surfaces or stone facets are to be prevented
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Determination of location through inclusions
The emerald is extremely rare and therefore one of the most valuable gemstones in the world. That is why extraordinary prices are charged for him. Inclusions do not reduce the value of emeralds. On the contrary: collectors are looking for these stones. They are considered the fingerprints of nature, the technical term is “Jardin”. There is also Emerald-Inclusions to beware of. Very specific inclusions that reach the surface of the gemstone reveal future cracks or fractures. Experts can distinguish these inclusions with a gemstone microscope.
Sometimes their origin is also decisive for the value of these stones. The most important emerald deposits are in Colombia and Brazil. African occurrences are also significant, for example in Zimbabwe, Zambia, Madagascar and Tanzania. A microscopic look inside can often reveal where the emeralds were found. Why? The inclusion image of a stone is, similar to the human fingerprint, an individual recognition feature. Here’s an example:
An emerald is examined under a microscope using bright-field microscopy. The appearance of three-phase inclusions in the emerald is not only proof that it is a natural emerald, but they also reveal the place of origin. It is an emerald from Colombia.
Purity grade in the diamond valuation
KRÜSS gemstone microscopes provide gemmologists and dealers with a tool that goes far beyond the classic 10x magnification of a loupe. A certified assessment can create security for buyers, especially when purchasing particularly valuable diamonds. The fine features and inclusions that determine the quality and price of a diamond can only be recognized under a gemstone microscope.
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More InformationKRÜSS stereo microscopes in practice
Our gemmological specialist, Dimitri Zlatev, demonstrates how the 4C diamond evaluation (Cut, Colour, Clarity and Carat) is carried out. He explains in particular the five factors of clarity grading: inclusion size, number of features, inclusion position, type/nature of the inclusion, and relief/visibility.
All of Dimitri’s videos can also be viewed on our YouTube channel.
Recommended standards and quality criteria for diamond grading
Clarity grades FL/IF–VS (flawless to very small inclusions) are determined as follows:
Almost every diamond contains natural inclusions. Stones with clarity grades FL appear flawless at 10x magnification, IF (Internally Flawless) are internally flawless and VS diamonds show very small, difficult‑to‑detect features. Experts use diamond loupes for the initial inspection. For professional grading or certification, our high‑quality stereo microscopes are widely used. For optimal handling during microscopy, we recommend using premium KRÜSS Optronic tweezers.
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More InformationKRÜSS stereo microscopes in practice
Untrained diamond assessment can lead to misdiagnosis. An experienced gemmologist knows the typical pitfalls – and Dimitri Zlatev demonstrates this impressively using the example of supposed inclusions.
The video reveals that the initial assessment of “inclusions” is misleading. In reality, there are multiple reflections in the pavilion facets that look like inclusions.
The result: what looks like a quality defect is actually an optical effect.
There are many other possible interpretations in the observation of internal inclusions. We have compiled a large selection of relevant specialist information with many interesting detailed photos on gem microscopy in the free whitepaper “Gemstone microscopes”. This specialist publication was produced in collaboration with Prof. Dr. Jochen Schlueter wrote. a qualified mineralogist in charge of the permanent collection on display at the Mineralogical Museum in Hamburg.
Do you want to read more?
Here you can order the free white paper “Gemstone Microscopes”, which describes many microscopic investigations and types of illumination. Simply enter your contact details here and we will send you our detailed white paper as a PDF on the subject of “Gemstone Microscopes” by email.