What Gives a Diamond its Color
Most commonly, the color of diamonds is caused by the presence of varying quantities of trace elements which displace some of the stone's natural carbon atoms within its crystal structure. Each trace element (e.g. boron, graphite, hydrogen, nitrogen or uranium) add a different color or hue. Other phsyical defects inthe crystal can also effect color. When more nitrogen than other trace elements connects with the carbon atoms in a diamond the stone becomes yellow, and the more nitorgen there is, the deeper that color becomes. Similiarly, the presence of boron produces blue diamonds while the presence of high levels of uranium produces green diamonds. Hydrogen atoms may be responsible for grey, violet and olive colors whereas pink, brown and purple diamonds get their hue from structural defects. It is still unknown exactly what specific elements are requed to produce red diamonds.
Hue, Tone and Intensity
The single most important factor in grading and valuing colored diamonds is the depth of color of the stone. The color, hue and tone of the diamond is compared to the lightness or darkness of the color to determine the grading, or quality of the stone. There are five recognized categories which independent laboratories use when there are grading a colored diamond: Fancy, Fancy Intense, Fancy Vivid, Fancy Deep and Fancy Dark (see table below). These are standards which have been recognized by international gemological authorities. Such standards provide assurances of the relative worth of colored diamonds. These recognized categories can also be found on the certificate of authenticity.
GIA Color Grading Scale:
|Faint||Very Light||Light||Fancy Light||Fancy||Fancy Dark||Fancy Intense||Fancy Deep||Fancy Vivid|
Color and RarityThe body color of a stone greatly affects the appearance of a diamond and its price. Color is part of the natural composition of the diamond and never changes over time. The most common diamond color is yellow, followed by orange, pink, green, blue and red (although a very vivid yellow diamond, for example could be worth more than a less vivid green diamond). Diamonds can also be made up of more than one color (e.g. a fancy intense greenish yellow diamond). Colored diamonds are categorized into 12 basic hues (the “dominant” hues) and their modifiers (the “minor” or “secondary” hues). These basic hues can further be classified into three different categories:
Colored Diamond Descriptions
The darkest color sensation evident to the eye and the mind. A nonspectral color the opposite of white, it is also a neutral color lacking saturation yet having a measurable range of lightness. Black is inherently dull in tone, yet individual black colors can vary in tone, resulting in pale (charcoal) black, dull (ink) black and bright (gun metal) black, all having weak saturation. Popular names for different mixtures of black are charcoal, gun metal, ink, jet, midnight, onyx and pitch.
Blue (B) - Bluish (B)
A perceived colour representing the sky on a clear day. Positioned on the spectrum between violet and green, blue may contain secondary colour modifiers such as blackish blue (bk-B), greyish blue (gy-B) and greenish blue (g-B). Alternatively, blue itself may occur as a secondary colour modifier as in bluish green (b-G), or bluish grey (b-GY). Popular names for mixtures of blue are; cornflower, indigo, navy, sapphire, sea and sky.
Brown (BR) - Brownish (Br)
A colour hue resembling chestnuts, chocolate, or freshly turned soil. In the diamond industry, the name brown is used broadly to denote a wide range of colour hues and tones. The lightness for brown diamonds is quite variable and includes a range from very light (smoke) brown to light (champagne) brown, medium (cocoa) brown and dark (coffee) brown through very dark (seal) brown. Saturation in brown diamonds is also variable, emitting tones such as bright (golden) brown and deep (cognac) brown.
A name used to identify a class of coloured diamonds (usually olive) that temporarily change colour after having been stored in darkness or when gently heated. Chameleon diamonds exhibit a range of hues and tones from light to dark olive (stable colour phase) through light to medium yellow (unstable colour phase). After 24-48 hours in darkness, exposure to light gradually changes the colour of a chameleon diamond from the unstable yellow phase back to the stable olive phase. This is observed as an infinitely repeatable process.
Not a colour but sometimes a modifying influence, fluorescence denotes the phenomena observed in certain coloured diamonds whereby they emit visible light (glow) when the excitation source of a higher energy (x-rays, cathode rays, ultraviolet rays or visible light) is turned on. Fluorescent diamonds exhibit different strength emissions, which are subjectively characterized as inert (non-fluorescent), weak, moderate, strong, or very strong, in a range of colours including violet, blue, green, yellow, orange, red and combinations thereof. Diamonds typically fluoresce in the following hues and corresponding common colour names: violet (mauve), blue (powder), green (moss or lime), yellow (lemon or mustard), orange (apricot or flame), pink (rose or salmon), red (blood) and certain colour combinations. Sometimes the term chalky is used to describe fluorescent colours that appear dull or subdued in brightness, and sometimes the term oily is used to denote fluorescent colours that exhibit a hazy appearance in an otherwise transparent diamond. For example, yellow and brown diamonds are said to exhibit a peculiar 'double colour' resulting from a combination of yellow or brown with a blue or green fluorescence.
Gray (GY) - Grayish (Gy)
A perceived color resembling the color of the metal nickel, aluminum, or pewter. Gray is a neutral color containing little or no saturation. The addition of small quantities of blue or green will produce a cool gray color, while the addition of brown or yellow will produce a warm gray color. Gray colors often appear very different when viewed under average natural daylight versus an artificial light source. Natural gray diamonds occur within a specific region of color tone. Their lightness extends from very light (smoke) gray, through dark (graphite) gray colors.
Green (G) - Greenish (G)
A perceived colour resembling the peel of an unripe lime or the gemstone emerald. Green is spoken of as being a cool colour when tinged with blue and a warm colour when tinged with yellow. The range of colour tone for green diamonds is variable in both lightness and saturation, resulting in pale (lettuce) green, bright (emerald) green, dull (laurel) green, and deep (forest) green colours. The majority of green diamonds occur in pale or dull tones with weak through moderate saturation.
Olive (OL) - Olivish (Ol)
A perceived colour resembling unripe olives. Olive is a modified spectral colour that is produced through a mixture of green and yellow with either grey or brown pigments of varying proportions. Olive colours in which grey or green are visually predominant are called cool olives, while olives in which brown or yellow predominate are known as warm olive colours. Popular names for different mixtures of olive are asparagus, avocado, chameleon, moss, sage and seaweed.
Orange (O) - Orangish (O)
A perceived colour resembling the average colour of an orange peel. Orange is spoken of as a warm colour. The range of colour tone for orange diamonds is quite variable in lightness and saturation, resulting in pale (cantaloupe) orange, bright (flame) orange, dull (burnt) orange and deep (marigold) orange. Other popular names for mixtures of orange are amber, apricot, autumn, carrot, cognac and salmon. One of the most exquisite of all orange diamonds is described as being of pumpkin orange colour.
Pink (PK) - Pinkish (Pk)
A modified spectral color that is often associated with flowers (carnations, roses) and seashells (coral). Pure pink colored diamonds with no trace of a secondary modifying color are extremely rare. Yet there are many variations of pink, and the label "pink" embraces a broad range of colors. Common names used to identify shades of pink are raspberry, strawberry, cedar, bubble gum, clover, and dusty rose.
Red (R) - Reddish (R)
A perceived color resembling the average color of the gemstone ruby, ripe strawberries, or fresh blood. Positioned on the spectrum between orange and the infrared, red is spoken of as a warm color. The range of color tone for red diamonds is small, limited in both lightness and saturation. Popular names for different mixtures of red are apple, autumn, blood, burgundy, cardinal, cherry, Chianti, china, claret, crimson, garnet, magenta, maroon, port, raspberry, rose, ruby, scarlet, strawberry and tomato.
Violet (V) - Violetish (V)
The colour violet (hue) appears in light through dark tones with a weak through strong colour saturation that may contain a tinge of blue (bluish violet) or grey (greyish violet), the average colour of the violet flower. Violet occurs in the spectrum between ultra violet and blue and is considered a colour on its own. Thecolour violet appears distinctly different from the adjacent hues (blue and purple) on the colour wheel. There are only two known pure violet diamonds certified by the GIA in the world.
(WH) - Whitish (Wh)
A perceived color hue resembling snow, refined sugar, or pasteurized whole milk. White is the lightest color perception evident to the eye and the mind. White is also known as a neutral (achromatic) color having no saturation yet having a measurable range of lightness. Popular names for different mixtures of white are cream, ivory, milk, moonstone, opalescent, pearl, salt, snow and sugar.
Yellow (Y) - Yellowish (Y))
A perceived colour hue resembling the average colour of the peel of a lemon or the petals of the dandelion flower. Yellow is also spoken of as being a warm colour. The range of colour tone for yellow diamonds is quite variable, especially in saturation, e.g., pale (popcorn) yellow, dull (ochre) yellow, bright (lemon) yellow and deep (amber) yellow. Popular names for different mixtures of yellow are amber, banana, buttercup, canary, citron, daffodil, dandelion, gold and marigold.