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Gemstone irradiation is a process in which a gemstone is exposed to artificial radiation in order to enhance its optical properties.High levels of ionizing radiation can change the atomic structure of the gemstone's crystal lattice, which in turn alters the optical properties within it. [1]
Such inclusions are usually formed during fluid assisted partial healing of fractures already present in stones. For this to take place in diamonds, high temperatures and pressure (HTHP) are required, which is unusual. Few such inclusions have been reported in natural blue and colorless diamonds.
Virtually all blue topaz, both the lighter and the darker blue shades such as "London" blue, has been irradiated to change the color from white to blue. Most green quartz (Oro Verde) are also irradiated to achieve the yellow-green color. Diamonds are mainly irradiated to become blue-green or green, although other colors are possible.
The clarity, or purity, of a diamond refers to internal inclusions of the diamond, and is one of the 4-Cs in determining a diamond's value.Common inclusions that appear inside diamonds are black carbon spots and small cracks, commonly referred to as fractures or "feathers", due to their feathery whitish appearance when viewed from above or through the side.
The majority of mined diamonds fall between white and pale yellow or brown; what is known as the normal color range. Diamonds of more intense color (usually yellow, but in some cases red, green or blue) are termed fancy color diamonds. Black diamonds are also fancy color diamonds. All other factors being equal, the most valuable diamonds are ...
Natural blue or blue-gray diamonds, common for the Argyle diamond mine in Australia, are rich in hydrogen; these diamonds are not semiconductors and it is unclear whether hydrogen is actually responsible for their blue-gray color. [21] Natural blue diamonds containing boron and synthetic diamonds doped with boron are p-type semiconductors.
Blue gold is an alloy of gold and either gallium or indium. [15] Gold-indium contains 46% gold (about 11 karat) and 54% indium, [ 4 ] forming an intermetallic compound AuIn 2 . While several sources remark this intermetallic to have "a clear blue color", [ 3 ] in fact the effect is slight: AuIn 2 has CIE LAB color coordinates of 79, −3.7, − ...
Only one percent of natural diamonds are of this type, and most are blue to grey. [30] Boron is an acceptor in diamond: boron atoms have one less available electron than the carbon atoms; therefore, each boron atom substituting for a carbon atom creates an electron hole in the band gap that can accept an electron from the valence band.