|
Sample Diamonds |
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|||
 |
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|||
|
|
|
||
| Fancy Diamonds: Diamonds when they first come to mind are generally white or colourless. They are highly valued for being as white or colourless as possible. However, even more valuable, partially due to their rarity, are fancy diamonds. This refers to diamonds that come in a range of colours such as red, dark blue, pink, green, amber and canary yellow. Diamonds of a definite colour are extremely rare. Natural coloured diamonds are basically a "stroke of nature". Brown [champagne/cognac], pink and red fancies are actually deformed diamonds. Defects in their crystal lattice structure change their colour. Blue and yellow diamonds have trace elements of boron and nitrogen in their makeup. While it is known which chemical processes cause colour changes. Black Black diamonds are opaque and although they do not show the fire normally valued in diamonds, they are still desired. The color is caused by inclusions of graphite within the crystal. The graphite inclusions cause the diamond to be a conductor.3 Diamond and graphite are both made of carbon, the carbon atoms are just bonded differently. Knowing this, it is not difficult to reason graphite being found in diamond. Gray Gray diamonds are colored by hydrogen, and more rarely boron (unknown how, since boron nearly always forms blue). The defect causes the stone to absorb all wavelengths of light equally. Gray color can tint nearly every other shade. Gray-greens are called "olive." White "White" diamond differ from colorless in that they are not clear. These diamonds are colored by inclusions so tiny that it is unknown the exact cause, though it may be from nitrogen. Some white diamonds are opalescent due to the scattering of light. Brown Browns are by far the most abundant color of diamond, and the least desired. Gem quality browns are often given elaborate names, anything to avoid calling them brown. Champagne is a code word for lightly tinted brown diamond. Darker browns are often called "cognac". The color in most brown diamonds results from parallel lamellae (like very small stripes). Red/Pink Pink and red diamonds are fairly rare colors, but have increased in numbers since the opening of the Argyle mine in Australia. Pinks often have a purplish tint. Like brown diamonds, these are colored by lamaelle of uncertain composition (the greater the number of lamaelle, the darker the color). The composition of the coloring agent is probably very similar since diamonds have been found that have both pink and brown lamellae.3 Orange Overall, the most infrequently occurring color of fancy diamond is orange. To be classified as orange, there must be a complete absence of brown to the stone. This color of orange is called "apricot." It is unknown what causes this coloration. There are so few actual oranges, especially ones of known mine origin, that it is difficult to study. The color was thought to be related to nitrogen inclusions, but this is unverified. Yellow Sometimes the 'pure' diamond you have in your ring is not clear at all, but slightly yellow. Slight yellow is almost considered a flaw, and often played down by yellow gold setting. No setting could disguise the intense color of the above diamond, an intense yellow. These deep yellows are much more rare than those masquerading as colorless. Some shades of dark yellow are called "canary." Most yellows are colored by molecules of nitrogen in the crystal lattice, though coloring through hydrogen is not uncommon. Green Green was thought to be caused only by exposure to natural radiation in the diamond's host rock. The radiation damages the crystal structure of the diamond, causing selective absorption. The problem with green diamonds, and the reason that a good one is so expensive, is that the radiation usually does not effect the entire diamond. It may be green only in patches or on the surface of the crystal. Faceting a diamond that is only green on the surface just cuts off the green color. Blue There are not any 'don't knows' when it comes to blues. Boron is often a coloring agent. In the gray-blue, the color is related to hydrogen. More rarely nitrogen is involved. When boron is the cause, the diamond is a semiconductor. Other causes do not yield conductive diamonds. Blues are also a very rare. Violet There seem to be no actual purple stones. No one has even discovered a way to make a purple diamond. What is called violet and purple are extremely rare. |
|||
|
|
|||
