Origin of the Yellow Color
Diamonds are made of carbon, but receive their color from natural impurities inside the diamond. Nearly all diamonds–mined and grown alike–have some impurities, with nitrogen being the most common. Nitrogen makes up over 75% of Earth’s atmosphere. During growth, a nitrogen atom takes the place of a carbon atom in the diamond lattice creating a yellow ‘color center’. This center absorbs all visible light except for yellow which is reflected back, giving the diamond its yellow color.
Generally speaking, the more nitrogen in a diamond, the more saturated the yellow color. If the diamond contains too much nitrogen it shows a yellowish brown color, which is common with industrial-quality diamonds. During growth, it is possible to capture the nitrogen in substances other than the diamond lattice, limiting the yellow color centers. These substances are called ‘getters’ and allow better control over the resulting diamond color. By limiting the amount of nitrogen in the growth cell, and capturing the excess with getters, we are able to produce desirable gem-quality colors.
The tone and saturation
of color gives our diamonds
their natural beauty
and range of color.
Many lab diamonds are available with an orange or yellow-orange color. This color is the result of a now outdated technology due to a type of a specific metal solvent used, and limited control over the diamond growth. The diamond is grown in a molten metal solution composed of various solvents necessary to create proper growth conditions. The orange color comes from solvents being trapped in the diamond lattice, along with the nitrogen, creating orange or orange-yellow color centers, depending on the concentrations.
While we still have some available, we are not actively producing diamonds with an orange modifying color.
Typical canary yellow color.
The most common gem-quality colored mined diamonds are pale yellows, usually called ‘canary yellow’. These range from a very light yellow to fancy light yellow. We have produced some ‘canary’ colors, but they are a pale or washed-out color and usually show color zoning. For these reasons, we focus most of our yellows toward the more saturated and desirable fancy yellow and fancy intense yellow colors.
Nitrogen helps the diamond to grow quicker than without. One machine cycle for a yellow diamond typically runs five to six days and will create one rough that could be cut into a one to two carat diamond.
Because yellows grow the quickest, they are the most available and least expensive of the colors. Though the price varies based on the specific color, carat, clarity, shape and other criteria, in general a one carat yellow is in the $3,300 to $5,000 range and a one carat orange-modified yellow is in the $2,000 to $2,600 range.
Mined yellow diamonds are most commonly available in the pale yellow colors and normally sell between $10,000 and $50,000 for a one carat.
Lab-grown yellow diamonds
cost about 1/4th the price
of their mined counterparts.
Rough yellow diamond grows in a truncated octahedral shape. This rough shape has the highest yield when cut into square shapes such as radiant, princess, cushion, emerald and asscher. Because of the larger sizes possible and demand, rounds are commonly available. Elongated shapes such as marquise and pear typically have low yields since the size is determined by the longest dimension of the squarish rough. For this reason, elongated shapes are not normally made.