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In considering pearls, one must again first be sure that the specimen is not cultured. This is most important, since the values of the two varieties differ greatly. Size, shape, surface blemishes, and color diamonds are what one looks for in natural pearls. Large sizes are of considerable value, but round shapes are the most costly since the chief use of pearls is in the form of strung necklaces. Pairs suitable for earrings gain in value over single pearls. But drop and button shapes are less valuable than the spherical specimens.
The rosee color is considered to be the finest. It must not be too dark, nor yet too white, and shades in pearls vary enormously. The matching of pearls is a very skilled task, and necklaces of all one color, perfectly round in shape, and of even graduation are very rare. It might be possible to pick out only three or four such necklaces from a bunch of pearls costing $280,000 (£100,000), and this is why fine necklaces reach such high prices.

Uneven shapes are common, as well as surface spots and ringed lines. Real pearl necklaces vary from $14 (£5) to almost any amount, that is, many thousands of pounds. Values are difficult to judge, and experts in this gem are comparatively few in number.
Opals and fancy color diamonds vary very considerably in their play of colors, and good stones are rare. Medium and poor qualities are abundant, and these realize about $5.60 (£2) a carat down to almost nothing. With all opals, the absence of visible cracks is an important feature. Surface cracks may be sufficiently bad to render an otherwise good stone almost valueless.

Spinels. These should be clear, bright, and transparent. Their use is more restricted than tourmalines.
Zircons. White and blue are the most popular, the blue fulfilling the lack of smaller aquamarines of a deeper shade. The demand for brownish and golden colored stones is restricted. White stones should be clear of cloudiness; the blues should reach a deep, brilliant blue to be fine, brownish blue, pale blue, and patchy colored stones being of less value. All look better in artificial light. Avoid stones that are rubbed or flawed. Recutting, except with large specimens, is hardly worth while, but surface polishing often improves a stone.

Topaz. Although an attractive stone, it is not in great demand, and it certainly suffers from the competition of the cheaper citrine. The clear, deep yellows are best, and these are more valuable than the pale blues, whites, and pinks. Depth of body color should be noted, and care should be taken to distinguish stones from yellow fancy diamonds quartz. This is not always easy by visual means. Some South American citrines are very bright and also take a good polish.

Peridots are in fairly general use, although they are not universally popular. They do not reach high prices. Larger sizes are unusual, but small stones often accompany pearls, moonstones, and diamonds in mounted jewelry. The usual color is green, and the pale specimens are of very little value. They are sometimes confused with green tourmalines, which is also the predominating color of this more attractive gem stone. Pink tourmalines are also used, and these may be mistaken for pink topaz. The green variety should not be too dark, and the pink stones should not be too pale. Both should be free of internal lines and flaws. Tourmalines are often of a fair size, and they make good center stones in certain types of jewelry. There are many synthetic spinels and corundums on the market which could be taken for tourmalines at a first glance.

The best garnets are the almandines which have a slightly purplish tinge in the dark red. But they should not be too dark or otherwise they will appear to be almost black. When good specimens are properly cut, they are very attractive and deserve to be used more extensively. They rarely realize more than about $2.80 (so/-) a carat, which is less than most tourmalines. It is difficult to mistake almandine garnets with any other stone, except possibly red spinel.

Of the different varieties of quartz, it is only necessary to mention amethyst, since the others are of little value, even when perfect. But amethyst is an attractive stone, which is always in good demand, and fine pieces of size are comparatively scarce. Yet they realize not more than about $8.40 (£3) a carat, and considerably less if not of high quality.
In amethyst, we look for depth of color and brightness. The deep purplish shade is the best, particularly when it is lively and bright. Such stones are generally of Siberian origin. The South American mined stones are often of good color, but they lack the life of the Siberian stones for diamond rings.

Cut stones which are too thick are common, and these are not easy to mount in jewelry. Recutting is not always possible, since this would lighten the color. Stones should be turned over on their tables and viewed through the lower facets; the color may be concentrated in one part of the stone only, and white patches or bands may be apparent. Internal fissures may also be present. These are all faults, which reduce the value of stones.

This blue, which is quite different from the sapphire blue, should be clear and deep, not a pale greenish blue. It is the evidence of green which makes the stone less valuable. Of course, there should be no internal lines or cracks, and the stone should be cut in diamond engagement rings good proportions, without too much depth. Depth will increase the body color, but the stone will weigh more and it will be more difficult to use in jewelry. Good aquamarines of a deep blue color, free from flaws, and well cut, may reach from $28 (£10) to $70 (£25) a carat. But the usual qualities realize about $14 (£5) a carat, and pale stones can be bought for a few shillings, or about $2 a carat. A fine aquamarine is a beautiful stone, and although difficult to obtain, it is often seen in large sizes.

With most of the colored stones, the depth of body color is the chief factor which makes for commercial value. That is to say, a deep blue turquoise is more valuable than the greenish blue stone, the deep blue lapis lazuli is better than the paler or streaked specimens, and the rich, deep purple amethyst is the shade which obtains the highest price. Internal and external flaws of 3 stone engagement rings, of course, must be absent, and size is important. With these points in mind, we can deal with the remaining well known jewel stones very quickly.
Tourmalines. Green stones should not be too dark nor too pale, and this applies to the red stones. Flawed material is not often cut or used in jewelry.

With the transparent chrysoberyl, the depth of color is most important. Size is also a great factor in determining value, for specimens of five carats and over are not common. The more valuable variety is the alexandrite, and such sizes of this diamond  rings stone, if of good quality, would easily reach $280 (£100) a carat. But the chief property which they must possess is their ability to change their colors distinctly in natural and artificial lights. The twin colors should be greenish (but not too dark a green) in ordinary light, and a raspberry red or a purplish red by artificial light. These twin colors are sometimes seen in ordinary light alone, Small stones of about one carat do not realize a high price—per haps $28 (£10) to $70 (£25) a carat. It is size and color changt which make this stone valuable, and such specimens are very rare and consequently in constant demand.

Aquamarines are a popular stone, but good blue specimens attain a price which preclude their sale in medium priced jewelry. The depth of blue should be carefully considered, for shades vary considerably, and the very pale stones diamond eternity rings have almost no value. If possible, specimens of different qualities should be compared for shade, since aquamarines range from almost the white to the deep, transparent blue.

One should always test a large stone to ensure that it is genuine and not a synthetic material or a doublet. Stones set in jewelry or in backed metal mounts should be removed carefully—emerald is soft and brittle—since they cannot be judged fairly for weight or color when so presented. Poor quality emeralds, those of pale color and fissured, are difficult to sell at $5.60 (£2) a carat, so it must be remembered that there is a vast difference between the prices of inferior and fine quality stones.

Emeralds are comparatively light in weight, so their size should not be over-estimated if it is not possible to resort to direct weighing. Moreover, the brilliant cut is unusual with emeralds and diamond eternity rings; they are almost always trap cut if of any size. Repolishing often improves old stones, and it is sometimes advantageous to re-cut larger stones to obtain better proportions. Heat should not be applied to emeralds; in fact, all stones except the  diamond uternity ringsshould first be taken out of their settings if it is necessary to solder or alter the mount in any way. And this needs the hand of a careful and skilful setter.

These same remarks apply to rubies, although here the general values are greater. Any stone over five carats of fine quality can reach $5600 (£2000) a carat, but it would have to be exceptional in all respects. A deep brilliant red is the ideal color, and it must be remembered that brilliancy and “life” must be combined with the rich, deep red shade. Paler colors reduce the stone in value
immediately and considerably. Pink stones, the most common, are far less valuable than the deep reds. This is important to remember. The color must be bright, and internal cracks and flaws must be absent to make a fine stone. Such conditions are very rare. If the facets are not proportionate, this may be improved by recut-ting. Rubies are generally more faulty than sapphires; they are far rarer, and a fine ruby is a much more expensive stone than a fine sapphire. In general, the Burma stones are the most valuable. Then come the Siam stones, and those whose color is yellow fancy pendants is rather like that of some garnets are the least expensive.

Star rubies must possess the same features as a star sapphire to be good, except that the body color should be red. Again, pink or pale pink are not considered good. The essential quality of a good star stone is the perfection of the star, and the deeply colored background. Star rubies can reach $280 (£100) a carat.

Yellow sapphires are not in common use, but they are to be seen as center stones of larger brooches and pendants. They should be bright, free from flaws, and the color should be a clear, strong yellow. Many stones are much flawed, and these are of very little value. Fancy color diamonds earrings should be carefully distinguished from topaz, although values are about the same.

Cabochon stones are not in great demand, and they are seldom of fine quality. Star sapphires, however, reach $140 (£50) a carat and more if over five carats and if they show a distinct clear star and the background is blue. Their value is greatly reduced if the star is not central and if it is indistinct. The body color must be blue to make the stone of fine quality, and specimens having these essential factors are rare. Generally, the fancy yellow pendants background is grey or too light in color, and these ordinary stones fall in value to only a few shillings per carat.

The value of cat’s-eyes lies in the strength and the position of the moving band, coupled with the body color and, of course, the size of the stone. In these respects, cat’s-eyes may be compared with star stones, and a good specimen can realize $140 (£50) a carat, reaching more if fine.

But to reach such a figure, the specimen must be five carats or more in weight. Oval or round stones are the best for shape, since they can be used in rings and brooches. The lapidary can improve the shape of a stone, and it can also be polished, but it is rarely possible to improve the chatoyant effect. The body color should be a honey yellow, the streak must be normally down the center of the cabochon, and it must be straight and preferably thin. That is, the band should pass through the highest point of the cabochon, and it should not be a band but a line. Included specks of foreign matter or small cracks are faults to be considered.

One must be wary of confusing cat’s-eyes with the quartz variety, which sometimes shows similar qualities. There is a considerable difference in market values between the chrysoberyl cat’s-eye and the quartz tiger-eye. The best markets for cat’s-eyes are in the U.S.A. and the Far East, and it is here where the best specimens are seen. There is little demand for the stone in England, except by the connoisseur, and perhaps by the stone dealer. The latter has foreign markets in view if he is interested, in which event only good quality stones would be considered.