The Essential 7C's
Diamond Inclusions & Blemishes
Inclusions and blemishes are structural imperfections which
affect the clarity grading of diamonds. Inclusions are largely crystals
of diamond or a foreign material that has formed within the stone
affecting the internal composition, while blemishes are flaws which
affect the stone’s surface. The size, number, colour, location,
orientation, and visibility of inclusions and blemishes are all taken
into account when evaluating the clarity of a diamond.
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
Crystals or Mineral Inclusions:
Diamonds regularly have miniscule crystals or minerals imbedded
within them and these can even be other tiny diamonds. Otherwise, any
included and undigested gemstones are more often than not fragments of
garnet, diopside, spinel, calcite, olivine, silica or iron oxide.
Although the majority of these cannot be viewed prior to magnification, a
significantly sized cluster or mass of crystals does detract from a
diamond's appearance, lowering its clarity grade and value.
These are cracks within the stone that resemble feathers. The
durability of a diamond is usually only affected if feathers reach the
surface of the stone, which is more susceptible to damage. Small
feathers under the surface do not normally create problems. Cleavage
planes or internal stress fractures can look like feathers, although
these are more commonly found, surrounding included-crystals.
An indented natural is one which dips below the polished
diamond’s surface. If a diamond has an indented natural, it would not
receive an IF clarity grade because the indented natural counts as an
Refers to a crystal inclusion that appears on the surface of the
diamond as a knot. Diamonds with a knot inclusion are usually awarded a
lower clarity grade as the flaw is visible to the naked eye (but not
These are long thin needle-shaped inclusions inside a diamond.
They appear as a streak of light inside the stone and can sometimes
appear in clusters, affecting the overall clarity and value.
Pinpoints are tiny light or dark crystals present within a diamond that appear either by themselves or in clusters.
More significant clusters of tiny pinpoints are referred to as
pinpoint clouds due to the white haze they create. Clouds are defined as
a dense grouping of tiny pinpoints, consisting of microscopically small
dust-like voids or impurities. The clusters create a cloudy zone which
even at 10x magnification may not resolve as individual pinpoints, thus
affecting the clarity.
These particular defects form as a result of the crystal
entwining into a trail during the original stone’s growth. This can also
be accompanied by graining and strain.