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Sapphire is the single crystal form of aluminium oxide (Al2O3). It can be found naturally as gemstones or manufactured in large crystal boules for a variety of applications.
Sapphire is any gemstone-quality corundum that is not red in color. (The red variety of corundum is ruby.)
When color is not specified, sapphire refers to the blue variety. Pink, yellow, green, white, and parti-color (multi-coloured) sapphires are often valued less than the blue variety of the same quality and size. However a pink-orange sapphire, called a Padparacha or Padparadja , is highly prized.
It is the impurities in the aluminium oxide crystal that give the color variations, with different impurity chemical elements giving the different colors that can be found. Pure sapphire is transparent. The crystals are exceptionally hard, with only diamond being harder among natural gems. They have a hardness of 9 on the Mohs hardness scale.
As well as occurring naturally, gem quality sapphires and rubies can be easily and cheaply produced in the laboratory. The chemical compositions and physical properties are identical to the natural sapphires. The tell-tale sign of synthetic sapphires is the crystalline growth lines which are usually curved due to the pulling during the accelerated crystal growth process.
The Logan sapphire is one of the largest blue sapphire gems known. It weighs 423 carats (84.6 g).
Lady Diana Spencer's engagement ring from Charles, Prince of Wales was a sapphire ring.Sapphire is also the birthstone associated with September.
See also: List of minerals Sapphire Mountford
Synthetic sapphire crystals can be grown in cylindrical crystal ingots of large size, up to many inches in diameter. As well as gemstone applications there are are many other uses:
The first ever laserFor alternative meanings see laser (disambiguation). A laser light amplification by stimulated emission of radiation is a device which uses a quantum mechanical effect, stimulated emission, to generate a coherent beam of light. Light from a laser is often produced was based on the ruby chromiumvanadium chromium manganese Cr Mo Full table General Name, Symbol, Numberchromium, Cr, 24 Chemical series transition metals Group, Period, Block 6 (VIB), 4, d Appearance silvery metallic Atomic properties Atomic weight 51. 9961 amu Atomic radius (calc. impurity in sapphire. While this laser has few commercial applications, the Ti-sapphire laserTi-sapphire laser or Titanium-sapphire lasers emit near- infrared light, tunable in the range from 650 to 1100 nanometers. These lasers are mainly used in scientific research because of their tunability and the possibility of generating ultra-short pulses is popular due the relatively rare ability to tune the laser wavelength in the red-to-near infraredInfrared IR radiation is electromagnetic radiation of a wavelength longer than visible light, but shorter than microwave radiation. The name means "below red" (from the Latin infra "below"), red being the color of visible light of longest wavelength. region of the spectrumThe noun spectrum (plural: spectra has a variety of meanings. Ghosts Originally a spectrum was what is now called a spectre, i. a phantom or apparition. Spectral evidence is testimony about what was done by spectres of persons not present physically, or h. It can also be easily modelockedModelocking is a technique in optics by which a laser can be made to produce pulses of light of extremely short duration, on the order of picoseconds ( 10-12s) or femtoseconds ( 10-15s). The basis of the technique is to induce a fixed phase relationship b. In these lasers, a synthetically produced sapphire crystal with chromium or titaniumscandium titanium vanadium Ti Zr Full table General Name, Symbol, NumberTitanium, Ti, 22 Chemical series transition metals Group, Period, Block 4, 4 , d Density, Hardness 4507 kg/m3, 6 Appearance Silvery metallic Atomic properties Atomic weight 47. 867 am impurities is irradiated with intense light from a special lamp, or another laser, to create the stimulated emission.
Pure sapphire ingots can be sliced into wafers and polished to form a transparent crystal slices. Such slices are used as watch faces in high quality watches, as the material's exceptional hardness makes the face almost impossible to scratch.
Wafers of single crystal sapphire are also used in the semiconductor industry as a substrate for the growth of gallium nitride based blue and green light emitting diodes.