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Diamond Inclusions

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What are Diamond Inclusions? The difference between Inclusions and Blemishes
Inclusions are flaws or imperfections in diamonds consisting of:

  • A defect within the crystalline surface of a diamond which are called inclusions
  • An abrasion or scratch on the surface of a diamond which are called blemishes
  • Laser lines generated during diamond enhancement procedures are also considered as inclusions

Inclusions are natural imperfections and often referred to as 'natureís fingerprints'. Some diamonds can have tiny crystals and minerals imbedded in them including other diamonds or even other gemstones. However, the majority of inclusions cannot be seen by the human eye.  

What causes Diamond Inclusions or Blemishes?
Some inclusions are caused by crystals of a foreign material or another diamond crystal. Other inclusions are caused by flaws in the structure of the diamond such as tiny cracks. Blemishes are flaws on the exterior surface of a diamond. These exterior blemishes are often the result of the cutting and polishing process.

What are the effects of Inclusions?
What are the effects on the quality, clarity and value of a diamond?

  • Inclusions interfere with light passing through the diamond and the stones ability to scatter and transmit light
  • The fewer inclusions a diamond has the more brilliant, rare and valuable it is
  • Diamonds which contain numerous inclusions are less brilliant and less valuable
  • A diamond's resistance to fracture is decreased if cracks are close to or breaking the surface of the diamond
  • Some inclusions can make a gemstone vulnerable to shattering
  • Only 20% of all diamonds mined have a clarity rating high enough for the diamond to be considered appropriate for use as a gemstone
  • Approximately 80% of all diamonds mined are relegated to industrial use

What do Diamond Inclusions look like?
The vast majority of inclusions cannot be seen by the human eye. They are located by a jeweller when viewed from above under a 10X magnification.

  • Minute cracks can often appear whitish or cloudy and could occasionally cause the diamond to split
  • Inclusions can be tiny colored spots including white, black, red or green

Inclusions and Clarity
The clarity of a diamond describes the presence or absence of inclusions within the diamond and any blemishes on its surface. Diamond Clarity is one of the 4 C s of diamond grading (Cut, Color, Clarity and Carat Weight). The numbers, sizes, colors, locations and visibility of inclusions and blemishes can effect the relative clarity of a diamond. Systems have been developed to grade clarity. Diamonds are graded for clarity on a scale ranging from flawless to imperfect. For additional information regarding diamond clarity please click the following link:

Diamond Clarity

Different Types of Inclusions
There are basically two categories of inclusions found in natural diamonds. Syngenetic inclusions formed at the same time as the diamond and Epigenetic inclusions formed afterwards. The names and descriptions of the different types of inclusions and blemishes, which affect a diamond's clarity to varying degrees are detailed below:

  • Bearding - Stress hair-like lines sometimes occurring during the cutting of a diamond
  • Carbon Spots: Black spots inside the clear diamond
  • Cavity - A large or deep opening in the diamond
  • Cleavage - A straight crack with no feathering
  • Cloud - A group of minute white inclusions resulting in a milky or cloudy appearance
  • Feather - A separation due to either cleavage or fracture which is often white and feathery in appearance
  • Internal graining
  • Irregular crystal growth which may appear milky, like faint lines or streaks, or may be colored or reflective
  • Knot - An included diamond crystal which reaches the surface of a polished diamond
  • Laser Lines - Vapor-like trails left behind when lasers are used to remove dark inclusions from a diamond
  • Pinpoints - Minute spots internal to a diamond.
  • A cluster of pinpoints can form a cloud


  • Scratches - A fine white line, curved or straight
  • Fracture - A crack on the surface of the stone
  • Nicks - A chip near the girdle or a facet edge
  • Pits - A minute opening resembling a white dot
  • Polish lines - Minute lines caused during this process

Diamonds are Forever...
An Impartial Guide to Diamonds

Clouds - Feathers - Knots - Cavities - Cleavage - Bearding - Internal graining - Blemishes
Polish lines - Grain boundaries - Scratches - Nicks - Pits

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