Blemishes in Diamonds: What are They?
When buying diamonds, one of the first things you check is the stone’s clarity.
You must have read somewhere that it can tell you the stone’s quality or grade. And you’re right.
Clarity is one of the four quality indicators (the 4Cs) used to determine and describe the stone’s value.
The other three Cs are Color, Cut, and Carat Weight.
A visual check will not likely show you the birthmarks and blemishes in a diamond.
You will need a jeweler’s loupe—a small magnifying glass that ranges from ten to twenty times magnification.
The absence of inclusions (internal characteristics) and blemishes (external irregularities) determine a diamond’s clarity grading.
Blemishes are the imperfections visible on the stone’s surface, while inclusions are located inside.
Blemishes such as chips, nicks, abrasions, and scratches occur after a diamond’s formation and during handling, mounting, and wearing a polished diamond.
Blemishes that appear during the manufacturing process are extra facets, polish lines, and burns.
Many of these diamond imperfections are not easily seen by unaided eyes.
A trained diamond grader with a visual instrument will see the diamonds’ birthmarks and blemishes, even if they are too tiny.
The common blemishes and flaws observed in diamonds are described individually below:
- Scratch: you will see this as a thin, white, dull line across the surface of the diamond. If magnified ten times using a loupe, you’ll see that a scratch is only surface-level and not deep.
- Nicks: on the stone’s facet junction, a small notch may be observed usually along the girdle edge.
- Abrasion: this irregularity is a series of tiny nicks along the facet junctions of a fashioned diamond. The edges will appear fuzzy or white.
- Polish Lines: these are tiny parallel grooves and ridges left by polishing. They are either white or transparent. The lines can occur on any facet, but they don’t cross facet junctions.
- Natural: this is usually observed on or near the girdle. It is a portion of the original surface of a rough diamond left on a polished stone.
- Burn Mark: a surface area that looks hazy. The excessive heat causes this during polishing. Another name for this imperfection is burned facet.
- Extra Facet: a facet that is not required by the cutting style and is usually placed without considering symmetry. Extra facets are often found near the girdle.
- Surface Graining: appears on the diamond’s surface. It results from irregularities in the crystal structure.
- Lizard Skin: looks like a bumpy or wavy area found on the polished stone’s surface.
- Rough Girdle: an irregularity characterized by a granular girdle surface.
- Pit: a small opening that looks like a tiny white dot.
Diamond inclusions are the internal characteristics found inside the stone. Some people refer to inclusions as the diamond’s birthmarks.
Research shows that the minerals inside the diamonds, causing the inclusions to take billions of years to form.
Scientists discovered that the difference in the inclusions found in diamonds depends on the diamond mine location.
The scientists studied diamonds mined from two different areas, which are miles apart, and observed distinct differences in the diamond’s inclusions.
Examples of diamond birthmarks are:
- Mineral or Crystals: some diamonds have tiny crystals or minerals trapped inside the stone. The crystals can be black, transparent, white, or black. If you see more colored crystals in a diamond, the brilliance of the stone will diminish.
- Clouds: these are a cluster of pinpoints or crystals that look like clouds when they are very close to each other.
- Indented Natural: an indented natural dips below the diamond’s polished surface. Diamonds with indented natural are not likely to receive an IF clarity grade.
- Needles: you will see long, thin needle-like inclusions inside a diamond. They look like a streak of light inside the stone. Sometimes, they appear in clusters.
- Twinning Wisp: the diamond has what looks like stretch marks, usually found in fancy shape diamonds.
- Knots: these crystal inclusions look like a knot. Diamonds receive a lower clarity grade if they have no inclusions. Often, the flaw is seen by the naked eye.
- Pinpoints: these are tiny dark, sometimes light crystals that usually appear in clusters.
- Feathers: these are cracks within the stone that look like feathers. If feathers touch the stone’s surface, the stone’s durability is affected.
- Chip: this is an opening on the surface or edge of the diamond. Corrections can be made by cutting and reshaping.
- Cavity: this inclusion looks like a hole in the stone’s center and is caused by a feather that breaks away.
- Bearding: this inclusion looks like beard hair and they often occur when diamonds are cut. If the diamond’s girdle is heavily bearded, it will look like it had been scratched.
What Are The Worst Inclusions In A Diamond?
Inclusions are imperfections inside the stone. And some inclusions negatively affect the diamond’s ability to reflect light.
Hence, the stones do not have a sharp, crisp, and glitzy appearance. Can diamond inclusions get worse? Yes.
The four worst inclusions in a diamond you should watch out for and avoid are:
- Black Crystals or Black Carbon Spots: if your diamond has black crystals or carbon spots, the light will not go through the diamond when it strikes the area where the black spots are.
- Top or Center-Located Inclusions: if your diamond inclusion is in the center or top part of the stone, it will destroy its brilliance. Do not buy a diamond that has a notable inclusion in this particular part of the stone.
- Long Needle or Crack: a long crack or needle is likely to run through the stone that if you accidentally slam the diamond against a wall, it might split into halves. Avoid diamonds with long needles or cracks.
- Clouds: small clouds will not have that much negative impact on the clarity of the stone. It’s another story if your stone has clouds that cover a big area. The stone will look milky or hazy and will diminish its brilliance.
Why Is There a Black Spot in My Diamond?
A diamond black spot is a natural flaw that usually occurs during the formation of the diamond.
The black spots are dots of carbon that have not fully crystallized yet.
If your diamond has black spots, don’t think that they are caused by cutting or handling.
At the time the diamond crystallized, the black spots were already there.
Black spots affect the diamond clarity quality.
And the worst part is that you cannot remove or get rid of these unsightly spots without affecting the diamond’s integrity.
Know the Clarity Grade of Your Diamonds
Worried that you don’t know much about diamond internal inclusions and what to avoid when buying diamonds?
At Shira Diamonds, our GIA certified gemologists will gladly check the stone’s quality and show you the clarity grade.