Syntetic stones
When considering rubies and sapphires, including the star stones, the prevalence of synthetics should be borne in mind, and large and apparently perfect stones should be very critically examined. Do not assume that all the rubies or sapphires in a piece of jewelry which contains many stones are real. Some may have been replaced by pastes or synthetics, and new pieces of jewelry containing diamonds and synthetic colored stones are not uncommon. Star stones are also simulated by star quartz suitably backed, especially in larger sizes. Stones in closed settings should not be bought if the amount involved is large, unless one is prepared to gamble. They may be doublets or synthetics, despite their apparent age or history. Rubies are relatively heavier than diamonds, but as they are often cut in forms other than the brilliant, their weights should be estimated with caution. Actual weighing by a balance is the surest means.
With emeralds, depth of color with brilliancy and the absence of flaws are the chief features to look for. A deep green, showing brilliancy, is the best, but stones are too often pale. Sometimes this is caused by the specimen being cut too shallow for want of sufficient material. Other stones are too dark, which also detracts from their value. Surface marks due to wear may be eliminated by careful polishing, but the lapidary cannot eradicate internal flaws. Such internal fissures and spots are most common in emeralds; in fact, a flawless stone is an exception, and some of the better specimens which reach $1,400 (£500) a carat and more are not entirely free of small flaws. A really flawless emerald of three carats or more might fetch a very high price (they have sold for
$5,600 (£2,000) a carat), so it is as well to examine such stones very carefully when they appear. But the color must be a brilliant velvety deep green to make the stone of first grade.