About Blue Colored Diamonds
Anyone looking for a natural blue diamond is out of luck—not only is it incredibly rare to find one, there is only one mine that produces blue diamonds in the world. It is the Cullinan Mine, near Pretoria, South Africa. This mine produced the Heart of Eternity, a famous natural blue diamond and the largest in the De Beers Millennium Jewels collection. Many of the popular shapes also look better as colored diamonds.
Blue diamonds fall under a Type IIB grade, although the diamond grading scale has occasionally changed. Blue colored diamonds can be formed from boron being scattered throughout the diamonds crystal structure or because of nitrogen atoms replacing carbon atoms, also within the crystal structure.
Most colored diamonds are originally yellow. They are exposed to radiation to change the hue and then these colored diamonds are treated with heat to maintain the change. There are also many different hues of blue diamonds. They can range anywhere from ice blue to deep aquamarine, all depending on how they are treated. Many of the lighter diamonds are produced using a high pressure, high temperature system rather than any type of irradiation.
Many ask what the upside is to using blue diamonds as opposed to using sapphires. The answer is that sapphires are much more expensive and lack the same sparkle and shine that blue colored diamonds do. Additionally, while sapphires are durable, diamonds are even more durable. Blue colored diamonds are available in all the same cuts and sizes as colorless diamonds and sapphires, though the color makes them more unique and timeless.
Blue colored diamonds, among other colored diamonds, require a little more specific upkeep than colorless diamonds. Colorless diamonds can be cleaned with pretty much anything available, while colored diamonds need jewelry cleaner approved by a jeweler because of the differences in the chemical makeup of colored diamonds. Certain chemicals in various cleaners, such as bleach (a common mistake for cleaning diamonds!), will cause even a colorless diamond to have a brownish tint and blue colored diamonds to lose some of their color.
Additionally, avoid heat while cleaning, because high temperatures can reverse the process used to change the color of the diamond and the color will be affected. This will also happen if blue colored diamonds are scrubbed too hard—the heat applied coating will come off, taking the color and shine with it.