The separation may seem easy using a loop, but documenting it with evidence is much more difficult.
The Old European Cut was the most common cut from about 1800 to 1940. The technological means of the time did not allow diamond cutters to process the material to the extent that they can today. This is why diamonds were cut either to produce a beautiful visual effect in candlelight that would become desirable to the buyer. Or with a view to retaining as much weight in carats as possible.
In 1919 the mathematician Marcel Tolkowsky published his paper on the Round Brilliant Cut design. His instructions are still followed today.
The work of the Tolkowsky analyzed in detail the way the diamond is cut ( Round Brilliant Cut ) so that it “returns” as many rays of light as possible to the eye of the beholder and changed the logic in the diamond market by adding another factor in the evaluation of diamonds, the quality of the cut. In fact Round Brilliant Cut has been around since 1950 , after the end of the Second World War.
There was a 20-year delay in the transition from the old to the new cutting between 1919 and 1939 and this was mainly due to two factors. On the one hand, advances in technology that gave better cutting tools to diamond cutters. On the other, the passing of the art from generation to generation, a slow process of improving diamond cutting techniques.
The confusion arises precisely with the diamonds cut in this interim period because some look like Round Brilliant Cut and some can be classified as Round Brilliant Cut with low grades in polish and symmetry.
The difference between the Old European Cut and the Round Brilliant Cut can be judged in very minor technical details. This is why the advice of an experienced gemologist is recommended.
Some of the factors that are diagnostic in determining the designation of the Old European cut compared to the Round Brilliant cut are:
Non-round shape - cutting
The means of the time did not allow the craftsman to give a perfect round shape to the octahedral rough diamond. Unlike the Old European Cut diamonds, the modern Round Brilliant Cut diamonds still have, as yet, slight deviations in diameter. These deviations, however, are not easily visible.
Small Trapezoid (In relation to diameter >53%) - cutting
The small trapezium is a feature often found in Old European Cut diamonds. This was because the trend of the time dictated keeping as much weight as possible. Consequently it was desirable to maintain a high crown and therefore more weight in carats.
In modern cutting it is considered a factor that reduces the quality of the cut considerably.
High Heads / Deep Cones
The higher the crown, the smaller the trapezium, a rule that applies even to modern round cuts.
Pasteurized Culet (Cone edge)
A characteristic that is very often found in Old European Cut and much less so in Round Brilliant Cut diamonds.
In Greece we often find Old European Cut diamonds that come mainly from antique jewellery. Their use was minimal in modern jewellery making. However, in recent years there has been a trend for jewellery designers to use them either by recycling old jewellery or by setting old cut diamonds in modern designs. In particular, diamonds weighing between 1.00 and 2.00ct are seeing increased demand and limited supply, which is expected to cause a rise in their price. Due to the increased demand , synthetic diamond manufacturing companies have used old cutting techniques resulting in the modern synthetic material resulting in an Old European Cut diamond , a combination that can be misleading as at the time Old European Cut diamonds were cut man had not yet managed to create diamonds in the laboratory.
That's why all diamonds brought in for inspection at the IGL are subject to control of their origin (synthetic or mineral). Regardless of their cutting.
Diamonds that have been cut with either the old or modern cut have their unique characteristics and can be used in modern and vintage creations or a combination of these by artists/jewelers. The characteristics and form of the materials enable jewellers to create special and unique jewellery.
The resulting jewel, however, must have the appropriate written documentation. In terms of the quality and characteristics of the materials, the style or even its uniqueness so that it can be safely passed on to future generations.
By George Spyromilios
Adamantologist
Source: independent Gemological Laboratory
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