The color of the sapphire is determined by experts gemologists visually, when compared with reference specimens. It is characterized by a combination of hue, saturation and lightness. The main color tone of the stone is a pure spectral blue, valid secondary colors – purple and green. Sapphires are also divided into five categories on the lightness and three categories of color saturation. However, for commercial purposes is usually applied a simplified classification of sapphire in color, which includes only three groups. First - bright blue sapphires; the second - medium-blue sapphires; and the third light blue sapphires.

The purity of the sapphire is also defined visually by the naked eye and with a magnifying glass with 10x magnification. Taken four groups according to the purity. The first is almost perfectly transparent sapphires without defects or with isolated small defects that are visible only under considerable magnification. The second - transparent stones with a few minor blemishes and natural inclusions that are not visible to the naked eye. Third - sapphires with a partial loss of transparency, with defects and inclusions that are very visible even to the naked eye. Fourth - sapphires with a marked or complete loss of transparency, with numerous, clearly distinguishable defects and inclusions (or defects are rare, but very large).

Weight of sapphires are measured in carats (1 carat equals 200 mg). Small stones of 1-2 carats are fairly common. Larger are considered sapphires 5 carats. They are very rare. The cost of 1 carat weight of the stone, depending on its color and purity, can reach $ 4,000.

Main ways cut sapphires – faceted and cabochon. From the facet most common cut is round, but often applied also fancy: "heart", "emerald", "Marquis", "oval" and "pear". Cabochon – a way cut in which the stone is given a round or oval convex polished surface. In this way treated sapphires with a significant loss of transparency and a large number of defects. Cut opaque sapphire cabochon with needle-like inclusions of the mineral rutile (so-called "star" sapphires) allows to identify the effect of asterism – the appearance of moving over the surface of a star with 6 or 12 rays.