September Birthstone

Sapphire

SAPPHIRE

Sapphire, the September birthstone, has been popular since the Middle Ages and, according to folklore, will protect your loved ones from envy and harm.  Medieval clergy wore sapphires to symbolize heaven, while commoners thought the gem attracted heavenly blessings.  Blue sapphires range from very light to very dark greenish or violetish blue, as well as various shades of pure blue.  The most prized colors are a medium to medium dark blue or slightly violetish blue.  Sapphire is a variety of the gem species corundum and occurs in all colors of the  rainbow.  Pink, purple, green, orange, or yellow corundum are known by their color (pink sapphire, green sapphire).  Ruby is the red variety of corundum.

Commonly, sapphires are worn in jewelry. Sapphires may be found naturally, by searching through certain sediments (due to their resistance to being eroded compared to softer stones) or rock formations. They also may be manufactured for industrial or decorative purposes in large crystal boules. Because of the remarkable hardness of sapphires—nine on the Mohs scale—and of aluminium oxide in general, sapphires are used in some non-ornamental applications, including infrared optical components, such as in scientific instruments; high-durability windows; wristwatch crystals and movement bearings; and very thin electronic wafers, which are used as the insulating substrates of very special-purpose solid-state electronics (most of which are integrated circuits).

Source of color

Rubies are corundum which contain chromium impurities that absorb yellow-green light and result in deeper ruby red color with increasing content. Purple sapphires contain trace amounts of vanadium and come in a variety of shades. Corundum that contains ~0.01% of titanium is colorless. If trace amounts of iron are present, a very pale yellow to green color may be seen. If both titanium and iron impurities are present together, however, the result is a magnificent deep-blue color.

Transparency and Hardness(Mohs Scale)

One application of synthetic sapphire is sapphire glass. Here glass is a layman term which refers not to the amorphous state, but to the transparency. Sapphire is not only highly transparent to wavelengths of light between 150 nm (UV) and 5500 nm (IR) (the human eye can discern wavelengths from about 380 nm to 750 nm), but is also extraordinarily scratch-resistant.
Mohs Scale of Hardness

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