These naturally-occurring colors fall outside the range of standard diamond color grading. The GIA (Gemological Institute of America) grades fancy color diamonds in the Z category, with 9 subcategories based on the intensity of the color (from 1- faint through 9 - fancy vivid). Diamond hue designations refer to color overtones (or the lack thereof) in the stone. Tone is used to denote how light or dark the stone is, ranging from very light to very dark.
Written off for most of the 20th century as "low color" industrial stones, brown diamonds have found their rightful place in today's jewelry fashions. Mined primarily in Australia, most from the famed Argyle diamond mine, the most popular brown diamond hues are champagne and cognac, but they range in color from light, pastel shades through rich, chocolatey midtones to the deepest dark browns. The brown color is believed to come from the pressure over time from being buried deep within the earth.
The names for the different shades of brown can a bit confusing for consumers! Early in the century, the term "chocolate" was commonly being used to describe all brown diamonds. Later, the term "chocolate diamonds" was trademarked by the manufacturer, Le Vian and is not used for any other jewelry today. The term "champagne", and some non-standard names like "latte" have replaced "chocolate" as the common (but inaccurate) designation for a brown diamond.
Read more - What's in a Name?
Champagne Diamonds - Sparkling like their namesake, champagne diamonds are a warm, golden brown. The term "champagne diamond" is also commonly used to refer to any fancy brown colored diamond.
Cognac Diamonds - Cognac diamonds are brown diamonds with a rich, deep, reddish/orange hue reminiscent of a fine brandy.
Other less-common brown diamond shades include Cinnamon (light pinkish brown), Honey (deep yellow-orange) and Clove (deep olive brown).
Some brown diamonds are actually lighter colored stones whose color has been artificially enhanced.
Yellow diamonds are found in mines all over the world and are very popular, with the pure, deep shades being preferred. Some of the most striking yellow diamonds are the vivid yellow diamonds found in Sierra Leone. Common terms for color variations include:
Canary and Daffodil - Pure, intense shades of yellow.
Sunflower - Intense yellow with an orange hue.
Some yellow diamonds have a brownish hue, ranging from Amber and Straw (light) to Banana and Golden Yellow (dark). Yellow hues in diamonds are caused by the presence of Nitrogen when the stone is formed.
Yellow color can also be produced or enhanced in diamonds through irradiation - a harmless, cosmetic process.
Beautiful and feminine, pink diamonds are often associated with the Argyle diamond mine in Australia. They can carry orange, purple or reddish hues, however pure pinks and reddish hues (like the intense "Strawberry" color ) are the most prized. Pink diamonds range in tone from light to dark and pale to intense. Intensely pink diamonds with a purplish hue are called "Bubblegum" diamonds .
Like brown diamonds, the color pink is thought to be caused by the Earth's pressure.
Natural black diamonds, especially translucent, gem-quality ones, are rare. Most get their color from the presence of iron oxides. They can be found mainly in the Central African Republic and Brazil.
One of the most famous black diamonds was the Black Orlov - a stone was stolen from a Hindu shrine and appeared to have been cursed, bringing bad luck and sad ends to all who owned it. Later, it was cut into three smaller stones - this seems to have mitigated the "curse" as owners of these stones have been unaffected.
Artificially enhanced black diamonds are the product if irradiation. They are affordable and commonly seen in fashion jewelry, especially in pave settings, similar to brown diamonds.
What comes to mind when you think of blue diamonds? Legendary beauties like the Hope Diamond or the Heart of Eternity? The Couer de la Mer in the movie Titanic? You might think with all this popularity that blue diamonds are common as colorless ones - they're not. In reality, blue diamonds are quite rare - found mainly in just one mine - the Cullinan diamond mine near Praetoria, South Africa. Their natural blue hues are due to the presence of the mineral Boron. [Learn more about blue diamonds and blue diamond jewelry.]
Blue diamonds can also be artificially produced through irradiation. Blue diamonds found in inexpensive fashion jewelry have been artificially enhanced.
Green diamonds are exceptionally rare, especially those that are pure green, without a yellow hue. The most famous green diamond is the Dresden Green Diamond - a pear-shaped, 41 carat natural green diamond. Green color can also be produced artificially.
Sometimes confused with green diamonds are the more abundant olive diamonds, which can have hues of green, yellow, black, gray or brown in combination. Olive diamonds have been found in the Central African Republic, the Congo and Sierra Leone.
Never heard of diamonds in these colors? Don't feel so bad - these colors are so uncommon that many jewelers and gem dealers have never seen them either!
Red diamonds are the rarest of all fancy colored diamonds.
The largest cut red diamond, the Moussaieff Red Diamond (formerly known as the Red Shield and pictured at right ), is only 5.11 carats! This trillion-cut diamond was discovered in Brazil in the mid 1990's. Another famous red diamond, known simply as the Red Diamond, was found in South Africa in 1927 - it is a flawless, blood-red stone weighing 5.05 carats. It is believed to be in a private collection.
Inexpensive red diamond jewelry contains diamonds which have been artificially colored red through irradiation.
True orange diamonds are highly sought after by collectors. Halle Berry wore the famous orange Pumpkin Diamond when she picked up her best actress Oscar. Another famous orange diamond is the Hortensia diamons - a 20 carat peach colored stone which belonged to Queen Hortense de Beauharnais of Holland - daughter of Empress Josephine. This stone is on display at the Louvre.
Purple is another extremely rare diamond color. Unlike other colored diamonds, true purple diamonds get their unique color from their internal structure - the right cut is vital to preserving their color. Violet diamonds are purple with a gray or blueish hue. There are, at present, no known famous pure purple diamonds, however arguably the Orchid Diamond, a 9.93 carat emerald cut diamond described as being a "pinkish lavender" color, is in this color family. The Orchid was cut in 1935 and sold to a collector in 1940. Its present-day whereabouts are unknown.