One of the first observations made by a gemologist is what is visible under magnification (10x loupe or binocular microscope with darkfield lighting) and inclusions have been one of the features looked at when grading the clarity of the diamond.
During the diamond formation small crystals and other materials that are trapped inside a diamond form inclusion and are found in both natural and lab-grown diamonds.
These imperfections that are formed due to different events occurring during formation can be more controlled for laboratory-grown diamonds, as they are formed with the aim to mimic nature.
Inclusions help gemmologists gain insights into the origin, formation and formation process in natural diamonds. Whereas lab-grown diamonds help identify the diamond growth methods.
Let's take a look at and compare the inclusions seen in both cases:
Natural Diamonds
These diamonds crystallize in the earth’s mantle and form inclusions during its formation from distortion in the structure during growth. These inclusions are what make the diamonds unique, as two diamonds having the exact same inclusions in the same place is highly unlikely.
The type of inclusions found in naturally formed diamonds are knots, twinning wisps, diamond crystals, other minerals, naturals, and indented naturals are evidence of the stone being a natural diamond.
Included crystal inclusion
Included crystals: they are smaller than a diamond crystal and appear white or transparent. These can be a crystal of different materials.
Knot Inclusion
A knot: is an included crystal that extends to the surface
Cloud of pinpoints, needles and crystals
Cloud of pinpoints, needles and crystals
Twinning Wisp Inclusion
Twinning Wisp: series of pinpoints, needles and crystals that look flat and ribbon-like and are associated with crystal distortion during growth.
Natural Inclusions
Natural: a location of the rough’s original surface left on a polished diamond. It shows smooth, irregular growth marks.
Lab-grown diamonds
There are two major growth methods for lab-grown diamonds. We will mention the inclusions that can be formed due to that.
HPHT grown diamonds
This is a process of using a metallic catalyst to stimulate the growth process and dissolve the carbon which migrates to the diamond seed. In some cases, the metallic catalyst doesn’t dissolve completely and becomes trapped in the diamond crystal.
Metallic Features
Metallic Features
These inclusions are formed from the non-melted flux which is solidified and shown when the diamond is cooled.
Metallic Needles
Metallic Needles
It is a very common inclusion seen in lab-grown diamonds and follows the growth pattern of the crystal forming along the faces and edges. They can be either very large or fine sizes.
Dendritic Remnants
Dendritic Remnants
It is not as commonly found. These inclusions resemble dark trees or bushes and occur when the flux in the molten state becomes trapped in the crystal.
CVD (Chemical Vapor Deposition) grown diamonds
Another way of growing diamonds is when carbon atoms are rained down on a substrate of a diamond seed. Therefore the diamond is formed in vertical layers. They don’t have metallic inclusions instead have graphite inclusions that lack the lustre of the metallic.
Cosmetic Remnants
Cometic Remnants
These inclusions take on a comet-falling appearance and are formed when crystals continue to grow after the appearance of dark inclusions.
Planar Clouds
Planar Clouds
These are a group of small remnants of impurities which form on a single geometric plane. You can see in the image that it has formed during the stops and starts of the growth process.
Internal Graining or Stria
Internal Graining
If shown as reflective angles or lines that appear milky-ish, coloured or reflective also caused by stops and starts of the growth process.
Here are some inclusions that are seen in both natural and lab-grown diamonds.
Bruise – A mark from a hit or impact that includes small feather-like patterns
Cavity - A big or deep hole in the gemstone
Chip – A small or shallow hole in the gemstone
Cleavage – A crack that runs parallel to a crystallographic plane in the gemstone
Cloud – A collection of small or very small growth traces that give a hazy look
Feather – A break or crack in a diamond that looks like a white feather
Pinpoint - A small dot-like growth trace.
It is extremely important to precisely analyse the inclusions of the diamond as they are a factor to determine the market value and identify whether its a lab-grown or natural diamond. Diamonds with no inclusions present a challenge to gemmologist in terms of identification and the need to rely on the atomic level characteristics.
It is always important to have an expert grade your diamonds. Book a consultation with us to grade your diamond if you are looking to buy or invest in one. Contact | Glaze Diamonds (glaze-diamonds.com)
And comment down below if you have any questions.
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