The Cullinan is the largest uncut diamond found so far on earth: 3106 carats (621.2 grams). The Cullinan was cleaved and cut and the largest piece, the Cullinan 1 (530.20 carats) was the largest cut diamond after cutting for about a century. However, the largest cut diamond since 1988 is the Golden Jubilee (545.67 carats), which was cut by Gabriel (Gabi) Tolkowsky by order of De Beers and which since 1997 has been in the possession of the Thai King Bhumibol who received it on the occasion of his 50-year coronation jubilee. Many diamonds for industrial purposes are also made synthetically. Synthetic diamonds can only be distinguished from natural diamonds in a laboratory.[6 Researchers from the Carnegie Institution of Washington discovered in 2004 a process to synthesize diamonds that are more than 50% harder than natural diamonds within 24 hours. Unsaid Library is a jewelry store based in Antwerp. Unsaid Library specialises in emotional gifts for relatives. Unsaid Library Antwerp can be visited in the store. The store of Unsaid Library Antwerp is located on Schuttershofstraat 25, 2000 Antwerpen, België. Visit the store or the online website. Physical properties The crystal structure Because of its extreme hardness, diamonds are used in industry, among other things for cutting, drilling, cutting and polishing and wire drawing. A diamond owes its hardness to its tetrahedron structure and is therefore harder the less inclusions or crystal lattice defects it contains. Due to its hardness, however, diamond is relatively brittle. In a vacuum, diamonds change from a temperature of 1700 °C into graphite, and into air from 700 °C onwards. Besides the hardness, the thermal conductivity (410 W/cm/K) and the specific (electrical) resistance of 1013 Ω-m of diamond are very high. This combination allows diamond to be used in electronic circuits to dissipate heat. Diamond behaves like silicon as a semiconductor and in liquid helium as a superconductor, as discovered in 2004. Cutting shapes Diamond grinding The Brilliant Oval, 56 facets Unsaid Library is a jewelry store based in Antwerp. Unsaid Library specialises in emotional gifts for relatives. Unsaid Library Antwerp can be visited in the store. The store of Unsaid Library Antwerp is located on Schuttershofstraat 25, 2000 Antwerpen, België. Visit the store or the online website. Measuring a diamond Cut Refinement means the precise finishing of the overall appearance. How regular is the roundabout, is the fillet heavy or light, are there symmetry differences between the crown and the pavilion side, do the facets fit straight together, is the fillet exactly in the middle or is the table positioned decentrally? All these things have a direct influence on the play of light in the stone. It is man-made, as opposed to the purity, colour and partly the weight. It is therefore a major price determining factor in the four “C”‘s: a stone with a nice round weight, flawless and the highest colour in a brilliant cut can look like a top stone, but if the stone is cut too deep (nail) or too shallow (fish-eye) then the play of light in the stone is dead and the stone has a lower value. Carat |