8/31/2023 0 Comments Large yellow gemsThus the history of the citrine is closely interwoven with that of the topaz, and coincides with it completely when it comes to the interpretation of alleged miraculous powers. However, the citrine is a member of the large quartz family, a family which, with its multitude of colours and very various structures, offers gemstone lovers almost everything their hearts desire in terms of adornment and decoration, from absolutely clear rock crystal to black onyx. And it does so at prices which are by no means unaffordable. The name is derived from the colour - the yellow of the lemon -, although the most sought-after stones have a clear, radiant yellowish to brownish red. Like all crystal quartzes, the citrine has a hardness of 7 on the Mohs scale and is thus, to a large extent, insensitive to scratches. It won't immediately take offence at being knocked about either, since its cleavage properties are non-existent. Even if their refractive index is relatively low, the yellow stones have just that mellow, warm tone that seems to have captured the last glow of autumn. Like golden Rhine wine or sparkling Madeira, heavy and sweet, citrine jewellery shimmers and brings a hint of sunshine to those dull November days. There are not many yellow gemstones in the world of jewels. However, the citrine fulfils everyone's colour wishes, from lemon yellow to reddish brown.Ī diamond or a sapphire may be yellow - those will be expensive -, or sometimes a tourmaline or chrysoberyl, though these tend toward green somewhat, a golden beryl or eben a pure topaz, which we will mention again later on. Rare though it is, yellow does in fact occur in quartz in Nature, if seldom, when there are traces of iron in the silicon dioxide. Historically, it has been found in Spain, on the Scottish island of Arran, in France, Hungary and in several mines overseas. Perhaps the citrine wouldn't have been talked about any more at all if, in the middle of the 18th century, it had not been for the discovery that amethysts and smoky quartzes can also be rendered yellow by so-called burning. This heat treatment at temperatures of between 470 and 560 degrees has to be carried out very carefully and requires a great deal of experience. However, in the course of 200 years, its application has become so much a matter of course that most of the stones available in the trade today are in fact burnt amethysts or smoky quartzes. Only a trained specialist can recognise the signs of heat treatment at all, burnt stones having subtle stripes whilst the yellow of natural ones is cloudy. In Europe, the boom on these yellow to reddish crystal quartzes didn't begin until, in the 1930s, expatriate agate cutters from Idar-Oberstein sent large quantities of citrine back home, along with amethyst and agate, from Brazil and Uruguay. Thus the golden-yellow quartzes made a contribution to Idar-Oberstein's becoming - and remaining - one of the world's great gemstone centres. Just as they had been used to doing with agate and other kinds of quartz, the cutters faceted the citrine using large, rotating sandstones over decades. The raw stone was actually held in the cutter's hand during this process. If you give that a little thought, it will occur to you just how skilled the cutters from the Hunsrück really were. The supply of Europe with sufficient raw material came just at the right moment for the nascent upheaval in social conditions.
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