Ruby

Ruby is thus named because of its res color(Latin-ruber). It was not until about 1800 that ruby, as well as sapphire, was recognized as belonging to the corundum species. Before that date, red spinel and the red garnet were also designated as ruby.
The red color varies within each individual deposit, so it is not possible to determine the source area from the color. The designations ''Burma ruby'' and ''Siam ruby'' are therefore strictly erroneous, and refer more to quality that origin. The most desirable color is the so-called ''pigeon's blood,'' pure red with a hint of blue.
The distribution of color is often uneven, in stripes or spots. The substance that provides thee color is chromium, and in the case of brownish tones, iron is present as well. As a rough stone, ruby appears dull and greasy, but, when cut, the luster can approach that of diamond. Heat treatment is commonly used to improve the color.
Ruby is the hardest mineral after diamond. However, the hardness varies in different directions. Ruby has no cleavage, but has certain preferred directions of parting. Because of brittleness, care must be taken when cutting and setting.
Inclusion are common. They are not always indicative of lower quality, but show the different between a natural and a synthetic stone. The type of inclusion (minerals, growth structures, canals, or other cavities) often indicates the source area.
Included rutile needle bring about either soft sheen (call silk) or, when cut en cabochon , the rare cat's eye effect, or more often the very desirable asterism-a six -rayed star, which shimmers over the surface of the stone when it is moved. Nowadays there are also Trapiche Rubies on the market. Their appearance is equal to the Trapiche Emeralds.

        Natural Ruby from Cambodia