![]() ![]() We cannot provide financial or legal advice. Specialising in insurance for certified diamonds for a replacement to make you feel secure with the right cover. “Marie Antoinette’s diamonds captured the world’s attention and achieved a fitting result for such a magnificent royal jewel.” ![]() “A very dynamic saleroom, coupled with strong online and telephone bids from around the world, resulted in lively bidding and a very high sell-through rate,” said Rahul Kadakia, international head of jewelry at Christie’s. In total, Christie’s sold 93% of items on offer, with bidders hailing from 32 countries. That piece had a high valuation of $2.2 million. A ruby bangle by Cartier, the first anniversary gift Wallis SImpson, the Duchess of Windsor, received from her husband, also remained unsold. The piece was estimated to bring in up to $10.9 million at the auction. However, a ring featuring a heart modified brilliant-cut, 6.75-carat, fancy-vivid-purple-pink, SI1-clarity diamond failed to find a buyer. A rectangular-cut, 42.98-carat, fancy-vivid-yellow diamond fetched $3.1 million, in the middle of its presale valuation, while a fancy-light-pink and colorless diamond brooch by Harry Winston hammered for $2.3 million, just over its lower estimate. A cushion-shaped Burmese ruby and diamond brooch by Van Cleef & Arpels brought in $4.6 million at the auction, smashing its CHF 600,000 ($656,756) upper valuation.Īn oval brilliant-cut, 43.19-carat, D-color, internally flawless diamond ring garnered $3.6 million, representing $83,000 per carat - within estimates. Other notable items sold at the auction include a pear brilliant-cut, 55.50-carat, D-color, potentially internally flawless diamond, which went for $5.3 million, or $95,700 per carat, at the high end of its estimate. In total, the November 9 auction raked in $59 million, with 11 lots fetching more than $1 million. In 2018, Sotheby’s sold a natural-pearl and diamond pendant belonging to Marie Antoinette for $36.2 million against its $2 million high estimate. That figure is the second-highest price for a jewel owned by the French queen and the highest price ever garnered for one of her diamond pieces. The set, made by Boehmer in 1776 and passed down through Marie Antoinette’s family for 250 years, fetched $8.2 million at Tuesday’s Magnificent Jewels sale, Christie’s said. It is well worth a read.Two diamond bracelets belonging to Marie Antoinette more than doubled their high estimate at a recent Christie’s auction in Geneva. Luckily that book has been written and is called The New Science of Strong Materials. So, like glass, once a crack has started it doesn't take a lot of energy to cause it to spread, so it may be stiff but it isn't tough.Ī fuller explanation of this took material scientists and engineers a long time to work out would require a whole book to do it justice. But it has no protection mechanism against cracks. Some very soft compounds are very tough because the deform so easily that it is hard to start cracks, nylon rope for example.ĭiamond is very very stiff. Some tough metals can adjust the micro defects in their crystalline structures to absorb the strain that would otherwise propagate cracks. But a bundle of glass fibres embedded in an epoxy resin can be very tough (because the cracks in individual glass fibres are not propagated through the epoxy resin). So a stick of glass will break easily as will a glass fibre. One key property of tough structures is that cracks don't propagate. The differences are in the crystalline structures. For example, stainless steel (used in knives and forks) is a well-known tough material but cast iron is brittle. we need to know a lot about the small scale structure of materials not just the substances involved. Understanding it requires some insight into why things break (and why other things don't). This is partially because it varies depending on circumstances in a way that stiffness does not and it is a property of the overall structure and not just the materials that make up the structure. Toughness is a vaguer term for materials and there isn't a simple way to measure it. (Hardness is not perfectly aligned to stiffness because of small scale microstructures in many materials, but this is good enough for now). If you try to poke them with something they resist deforming to accommodate your poke. Glass and diamond are very stiff materials, for example. Hardness is strongly related to the more well-defined quantity of stiffness which measures how easily a compound can be deformed under stress. Hardness and toughness are very different qualities in materials and are weakly related. ![]()
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