Suomen Gemmologinen Seura ry
Sähköposti
info@gemmoseura.fi
info@gemmoseura.fi
Place: Helsinki Central Library Oodi, Töölönlahdenkatu 4, 00100 Helsinki
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Place: Helsinki Central Library Oodi, Töölönlahdenkatu 4, 00100 Helsinki
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Stock Exchange House in Helsinki (Pörssitalo), Fabianinkatu 14, 00100 Helsinki
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Dresscode: x
Seminar presentation: From UV lamp to spectroscopy: how to get the most out of your equipment
Luminescence is a very sensitive, and thus very powerful technique. Unfortunately it is not used to its full possibilities in gemology. Gemological observations are still being done with classical UV lamps, but many alternatives are now possible, just as easy to use, such as lasers, but also specially-made luminescence instruments such as the Diamond View, mostly for labs. We will explain how to do a good description of the luminescence of gems, not forgetting any character that might be relevant. We will give examples of why this is relevant, and some extra things that can be done with just classical gemology to have a hint of the cause of luminescence for example. Independently from classical gemology, luminescence spectroscopy has become a routine method in many industries. We will briefly explain how the cause of luminescence is unraveled, on the example of shortwave blue luminescence seen in many gems (sapphire but also tourmaline, opal, glass and others) and minerals, related to titanate groups.
Seminar presentation: The Plastic Deformation Game: The Link Between Olive, Brown and Pink to Purple to Red Diamonds and Their Color Origin
The diamond structure is known to be rather rich in defects, either incorporated directly during the growth process or introduced after growth. Post-growth processes that introduce defects in the diamond lattice include natural irradiation – mostly from radioactive fluids – and plastic deformation. Sheering and faulting of the surroundings after diamond growth result in plastic deformation of diamonds. Such plastic deformation results in dislocations and when these dislocations move, they create slip. A dislocation is a linear (one-dimensional) disruption in the regular, repeating atomic structure; on a structural level this means that bonds break and re-form when the diamond is deformed, and because this happens for relatively small number of atoms, the diamond stays completely intact during this deformation; meanwhile the crystal lattice becomes highly defective within the slip planes. In diamond, these slip planes are parallel to the octahedral crystal faces. The ruptured bonds result in massive amounts of vacancies, which can form various defects, the most common ones being H3 centers (an A center plus a vacancy) and vacancy clusters. Colored diamonds with strong plastic deformation include “olive”, brown and pink to purple to red diamonds. The defect defined as responsible for the brown color of diamond is the so-called vacancy cluster, which is a large aggregate of accumulated vacancies. The color origin of all otherwise colored diamonds is clearly linked to the defects of brown diamonds, but the exact nature is currently unclear. Significant research has been conducted by our laboratory concerning the still puzzling color origins of these diamonds and their defect characterization. Work performed by our lab on “olive”, brown to pink and red diamonds with the aim to understand why plastic deformation can produce these colors has pointed towards the temperature during plastic deformation events being responsible for the different hues. The different temperature conditions result in somewhat different vacancy-cluster-type defects and in consequence the different colors.
Seminar presentation: The Changing World of Gemology – Gem Testing: A Look Back and a Look Forward
This presentation will focus on a brief historical review of the development of some gem-testing methods, a summary of current gem testing and research at the GIA Laboratory, and comments about ongoing and some possible new gem identification challenges.
Seminar presentation: The Evolution of Gemmological Photomicrography-Film to Digital
This presentation will examine the history of photomicrography in gemmology and review the technological improvements that have occurred over the last century. The presenter will also showcase a suite of comparison images that were recorded on film and recreated modern digital equipment for direct comparison.
Seminar presentation: Certified Hybrid Diamond Master Set – The Hybrid Solution for Diamond Color Grading
The GIA-certified diamond master set has long been the globally accepted standard for diamond color grading. It is considered a critical component in gemological equipment wherever accurate color grading reports are needed. Additionally, it is required by many gemological and appraisal associations for laboratories seeking accreditation. However, obtaining a GIA master set has always been a complex and costly process. The strict criteria for inclusion, combined with the limited number of companies able to supply diamonds of the necessary quality and volume, has led to a steady decline in availability—eventually resulting in a complete halt in supply. The issue has been compounded by the declining quality of Cubic Zirconia (CZ) master sets. For years, only one company had produced stable and consistent CZ series, but it has since run out of rough material and has no plans to resume production. As a result, gemologists have been left without a reliable alternative. In 2023, several American gemological associations and appraisers held multiple meetings to find a solution, but no clear consensus was reached. Members of the Accredited Gemologists Association (AGA) began discussing a new concept: a “hybrid” master set combining synthetic diamonds for the higher color grades and natural diamonds for the lower ones. This marked a significant departure from traditional methods, which exclusively used natural Cape series diamonds, whose yellow hue comes from N3 nitrogen aggregates. The idea of using type II synthetic diamonds—completely nitrogen-free—was considered controversial and, initially, not feasible. However, a purely visual testing approach was adopted, independent of spectrophotometric analysis, to determine its viability. Since the GIA does not issue master set certification reports for synthetic diamonds and therefore could not support the project, the team turned to Sarine-GCAL. With its new proprietary AI driven instruments for automatic color and clarity grading, GCAL was well-positioned to help evaluate the hybrid concept. Initial tests showed positive results, and the team moved forward by selecting Stuller as a partner company with the ability to supply both lab-grown and natural diamonds in sufficient quality and quantity. One key requirement for Stuller’s involvement was a firm commitment to keep the hybrid master set permanently available, regardless of sales volume. All parties involved shared the view that the project was driven not by profit, but by a responsibility to support the gemological industry with reliable tools. The Stuller–Sarine/GCAL collaboration officially began in August 2024. By February 5, 2025, the first hybrid master set prototype was unveiled at the AGA Conference in Tucson. The set includes eight diamonds: synthetic stones for colors E, F, and G, and natural stones for H, I, J, K, and L. Attendees at the conference were able to visually test the set using certified diamonds, and early feedback confirmed its accuracy and consistency. Following this success, the AGA updated its certification criteria for CGL (Certified Gemological Laboratory) status to include GCAL-certified master sets alongside those issued by GIA. Several other professional associations have already expressed their intention to adopt the same policy. For more information, including answers to common questions and a registration form for updates or pre-orders,visit the AGA’s dedicated webpage https://accreditedgemologists.org/hybrid-diamond-master-sets/ According to Guy Borenstein, the Stuller representative for the project, the first hybrid sets should be available between October and November 2025.
Seminar presentation: BIOGENIC GEMS & CITES: a look into pearls and corals
The use of biogenic gem materials may raise questions regarding the impact on biodiversity of their use in the decorative arts, specifically in jewellery. Since 1978 that an international convention, CITES, is in place to address these issues. Ivory, bone, tortoiseshell, ebony, shell, mother-of-pearl, pearl, coral, gastric concretions, vegetal nuts are a few examples of gem materials of biological origin that require appropriate import/export knowledge for their trading. In this talk after clarifying what are the three CITES Listings we’ll focus on natural pearls and precious corals.
Seminar presentation: Paraiba and other gem varieties of the tourmaline group
Tourmaline surpasses all other gemstones by its wide range of colours. The group includes a number of complex boron-aluminium silicate minerals with structures that allow the incorporation of almost any chemical element. The large range of chemical variation leads to a number of different tourmaline minerals such as elbaite, by far the most common gem tourmaline, liddicoatite, dravite and schorl. At the end of the 1980s, unusual vivid blue and green elbaite tourmalines from the Paraíba State in northeastern Brazil generated major interest in the gem trade due to the discovery of new colours that had never been seen before in this gemstone species. In just a few decades the ‘Paraiba tourmaline’ developed to one of the most sought-after gems in the world. The increasing interest in tourmaline has led to an increasing demand of other gem tourmalines including indicolite and rubellite as well as ‘Canary’ and ‘Lagoon’ tourmalines. This presentation will focus on the geology, compositional characteristics, nomenclature, enhancement and imitations of gem quality tourmaline.