Platinum and silver - Platinum is much more costlier than gold, while silver is fairly cheap. Platinum is combined with other metals such as palladium, ruthenium, rhodium, and osmium and like gold jewelry; platinum also comes with quality markings indicating the proportion of platinum used. Markings however are based on parts per thousand, thus 900 platinum marking signifies that 900 parts out of thousand parts is pure platinum or the jewelry item is made using 90% platinum. Jewelry items made from less than 850 parts per thousand pure platinum will include markings indicating amount of platinum used as well as the amount of other platinum group metals mentioned above.
Silver jewelry that contains 92.5% silver is also called sterling silver and may be marked as 925 meaning 925 parts per thousand are pure silver. Like gold, silver plated jewelry is also very popular.
Gemstones - You may have the option of buying natural stones or those created in laboratories. Laboratory-created stones have the same physical, and chemical properties as natural ones and even look similar. They are cheaper versions of natural stones due to their easy availability and are your best bet if you are looking for an exact replica of natural stones minus the hefty price tag. On the other hand, imitation stones (made of glass, plastic or other materials) that are available in the market only look like natural stones and must not be confused with laboratory-created stones.
This article is about real pearls, both natural and cultured. First, the term 'pearl' should be applied only to natural pearls, formed in a mollusk when some event in nature induces the oyster or mussel to form a pearl. These pearls are quite rare and are the pearls of antiquity before pearl farmers learned to culture pearls. Freshwater pearls fished from the rivers in the USA are natural pearls, but now-a-days, most freshwater pearls are also cultured in freshwater pearl farms.
In any event, naturally forming or cultured, such pearls are formed in the oyster or mussel and are not fakes. The real difference in the totally natural pearl and the cultured pearls is what makes the pearl start to grow and the thickness of the nacre. Nacre is the pearly layers that make a pearl so lovely. The natural pearl will have very thick nacre, generally forming in concentric rings around some starting source or irritation to the mollusk. A large natural pearl is very, very rare. Cultured pearls generally use a 'core' of mother-of-pearl, the shell of the mollusk.
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Orignal From: Platinum and silver
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