THE RUBY AND THE SAPPHIRE

Ruby and sapphire are both well known precious stones, and it may be thought that they are entirely different in character and species. This is not so, for chemically they are of exactly the same material and it is only the color of a given specimen which determines whether it be called a ruby or a sapphire. The red stones are named rubies, and other colors (not only blue) come under the general name of sapphire. Chemically, they are all corundum, an oxide of aluminum, a natural compound which must not be confused with Carborundum. A chemical analysis by the spectrograph shows that, although alumina (aluminum oxide) is the main constituent of corundum, other metallic oxides amount to about three per cent of its composition.

Everyone knows the rich red color of the ruby and the deep blue of the sapphire, but it must be remembered that there are other beautiful red and blue stones which are neither ruby nor sapphire. It is one of the most popular stones beside diamonds, and can be used like diamonds are used for diamond rings, bridal sets. Of their respective colors, however, ruby and sapphire are the rarest, most costly, and certainly the most popular of gem stones. Of course, in order to bring out the attractive colors of these transparent gems, careful cutting and polishing are required, and it will be found that perfect specimens free from internal marks or variations of color are comparatively rare. In fact, layers or patches of color are frequently seen within the one stone; parti­colored stones are common, and flaws in the form of "silk," cracks, and spots are quite usual.



Corundum, from which these gem stones are cut, occurs in crystals which belong to the hexagonal system. Ruby generally occurs in crystals of six sided prisms and sapphire as twelve sided prisms. But red and blue are not the only colors found. Almost every shade may be had, and with the exception of the red (ruby), blue (sapphire), and the pure white (white sapphire), these other colored varieties are generally referred to as "fancy sapphires."

Yellow stones are known as yellow sapphires, but sometimes as oriental topaz or king topaz; green stones are known as green