What Are Diamond Impurities?
Diamonds are made up of carbon, and any other substances present in a diamond are referred to as impurities. Some of the most commonly found diamond impurities are atoms of nitrogen, hydrogen, and boron.
Diamond impurities may cause a stone to look tinted, and the intensity of the color will depend on the concentration of the foreign atoms within the structure of the stone.
For example, a diamond that contains a high concentration of nitrogen will have a strong yellow color, but a stone that has only a small number of nitrogen atoms in its crystal lattice will have only a faint yellowish tint.
Diamond Inclusions (Flaws) vs. Diamond Impurities
People use the word “impurities” to also refer to diamond inclusions, which are physical flaws that are visible with the naked eye or under 10x magnification.
Although “inclusion” and “impurity” are sometimes used interchangeably, the latter term is often used to denote a foreign substance that affects the color of a stone and can be detected at the atomic level but is not visible as an isolated flaw.
Examples of inclusions include such defects as surface nicks and blemishes, as well as internal lines, black dots, and clouds, among others. Foreign crystals visible as points or needles inside a stone are also considered inclusions.
Finding Impurities in Diamonds
Since chemical impurities alter the color of a diamond, the best way to detect them is to look for tints in the stone.
Diamonds with little to no impurities look perfectly white, or colorless, so if you have such a stone at your disposal, you can compare other stones with it to see if they have visible hues.
Alternatively, if you don’t have a diamond that is graded Colorless, you can use a perfectly white background as a backdrop against which to look at a stone and see if it has any color that makes it look tinted or darker in comparison.
If your diamond is mounted in a nonwhite setting, such as one made of yellow gold, it is best if you test the stone for impurities when it is loose; otherwise, the color of the metal will make the diamond look colored.
Different colors signal the presence of different substances in a stone.
For example, yellow color is a sign of nitrogen impurities, as already mentioned. Blue color is caused by the presence of boron atoms.
A high concentration of any substance can give a diamond an intense color – such stones are considered fancy-color diamonds, and they can be quite expensive because of their rarity.
How to Spot Diamond Inclusions
Diamond inclusions are best seen under magnification.
If you have a 10x loupe, you can use it to look at the stone and see if you can spot any specks, clouds, dark spots, or lines. If you are having a hard time seeing any of these, then the stone is of high clarity.
(Visibility under 10x magnification is the standard used in diamond grading to determine whether an inclusion is present.)
The next test to spot diamond inclusions is to see if there are flaws visible with the naked eye.
Look at the top of the stone from a normal viewing distance (around 10 inches, or 25 centimeters). If you cannot detect any visible defects, then the stone can be classified as eye clean, i.e., it doesn’t have inclusions visible with the naked eye.
It is true that diamonds that look clean under a microscope are preferred by jewelry buyers, but these stones are also very expensive.
A diamond can have inclusions visible under magnification, but if these flaws are invisible to the naked eye, why pay more for perfection nobody would be able to see when the stone is worn?