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Stones: Properties and use
We use both natural and treated natural stones, but no synthetics or imitations. According to law, any treatment or enhancement of stones must be disclosed. Pearls are cultured. Carat weights are given to the lower 2 decimals. If a piece has multiple stones, the total carat weight (tw) is given. Whenever known, the country of origin is stated. Sapphire: We use no synthetic, assembled or imitation stones. However, most sapphire has been heat treated, with the exception of a few stones. This heat-treating takes place in Thailand where most sapphire is cut. The process consists of taking both cut or rough sapphire that contains the coloring agents iron and titanium and heating the stone almost to the point of melting so that the iron and titanium diffuses into the body of the stone, thus imparting a blue color. This process can also make light blue sapphires a deeper, richer blue. Sometimes, the blue color of a stone can be ruined instead. Many sapphires contain minute needles of the mineral rutile called "silk" which can impart a velvety appearance to the stone. Heat treating dissolves this "silk" and results in a clearer stone. Heat treatment is considered to be permanent. Sometimes the needles of rutile will line up along planes within the sapphire and this produces the star effect. We examine our sapphires to be sure they are of natural origin. Ruby: We use no synthetic, assembled or imitation ruby. However, most ruby has been heat treated, with the exception of very few stones. This heat-treating takes place in Thailand where most ruby is cut. The object is to improve the color by driving off materials such as iron oxide that might detract from the color which is produced by the presence of chromium. However, a glass-like material is sometimes used to fill nicks and other surface imperfections, and add to the weight. This filler flux material is detectable with good microscope technique and we reject such stones. We also examine our rubies to be sure they are of natural origin. Emerald: We use natural emeralds, no synthetics or imitation. Emeralds derive their color from the presence of chromium, and sometimes by vanadium as well. All emerald material has been treated at some stage after it has been mined. The miners oil their rough immediately after extraction and before sale to a dealer or cutter; cutters oil or use an epoxy type material, sometimes tinted. The epoxy type material is to hold together stones that might otherwise crumble or break, as well as to fill feathers, cracks and nicks in order to increase the transparency. Using a microscope, we examine stones for epoxy and oil, and if the use of oil is minimal, ultrasonic the stone for a period of time which removes the oils near the surface. If an emerald can't stand ultrasonic cleaner treatment we don't use it. Emerald is one of the most heavily treated colored stones, and due to the nature of emerald formation in the ground that causes many imperfections to be incorporated into most stones, it is delicate. But beautiful! Lapis Lazuli: Our lapis comes from Afghanistan, probably smuggled to Pakistan. Our material is not enhanced in any way. Some of the lapis is cut and polished by us. Calcite and pyrite occur naturally in lapis, and we tend to find the contrast with the blue an interesting variation. Tourmaline: The tourmaline that we use comes from several sources. The larger stones are from Maine, mostly from the Plumbago Mine in Newry. The small slabs and beads are from Brazil, we think. Tourmaline is sometimes treated by moderate heating. The Maine material is not treated, but the Brazilian may have been treated - but we can't be sure either way. Tourmaline, while not as hard as sapphire or ruby is tough and resists nicking and breaking. Opal: The opal we use is mostly from various mines in Australia. Many stones are completely transparent opal. From Mexico come fire opals, beautiful orange stones with opal's trademark play of color. Other stones are "boulder opal": a layer of opal attached to its underlying ironstone matrix. One side of the stone-to-be is finished by grinding off the ironstone matrix until the layer of opal is reached. Then some of the bottom of the stone is ground off leaving a substantial ironstone layer supporting and attached to the Fire Opal. Then the stone is shaped so as to retain the maximum area of Opal and yet have a nice shape. Finally, the exposed fire opal is carefully polished. The Fire Opal top is rarely flat or rounded. It is usually smoothly uneven and of varying thickness. The combination of Fire Opal attached to it's ironstone matrix results in a stronger stone and the dark color of the ironstone contrasts with the top layer of opal adding to the display of fire. However, opal is not a very hard material and is somewhat brittle. Therefore opal rings must be treated with respect. The opal we use has been thoroughly dried to avoid crazing from water loss. We do not use doublets or triplets. Pearls: We use cultured pearls from Japan, China and the South Seas, primarily Tahiti. Japan was the foremost producer of both saltwater cultured pearls and freshwater from Lake Biwa. Because of water pollution problems, Japanese cultured pearls have become fewer and more expensive. Chinese cultured pearls are now of very good quality, both saltwater and freshwater and more reasonably priced. The dark gray or green-gray of South Sea pearls are distinctive. They are cultured in warm saltwater and are usually larger. Saltwater cultured pearls are cultivated by inserting a shell bead nucleus into the mollusk which acts as an irritant around which nacre is deposited. The Japanese saltwater are usually a shade of white and round in shape and can have very nice luster with overtones. Freshwater pearls are the result of a little piece of mantle tissue being inserted into a mollusk of a larger species, one which can produce many pearls at a time. Freshwater pearls are therefore all nacre, and are of various shapes and sizes, taking on the color of the mollusk that is chosen. The quality of the pearl in both instances depends on the length of time the mollusk is left underwater. They are harvested and cleaned with a little bleach. Pearls are organic matter and need some consideration because the surface will wear with hard use.
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