Impurities and inclusions in diamonds

The purity of diamonds in detail: Everything about impurities and inclusions.

When it comes to the clarity of a diamond, a distinction is made between inclusions and blemishes. Inclusions are found inside and blemishes on the surface of the diamond.

What types of inclusions are there in diamonds?


Crystal - crystal

  • During the creation of the diamond, a crystal of minerals was embedded inside the diamond.
  • The crystals vary greatly in size.
  • Crystals exist in all colors.

Needle - needle

  • Needles are elongated crystals inside the diamond.
  • Needles usually appear white or dark (gray or black).

Cloud - cloud

  • A cloud usually consists of point-like inclusions that are close together and can hardly be told apart.
  • The accumulation of inclusions appears like a cloud or mist and may be somewhat milky or even opaque.
twin wisp

Twinning Wisp - twin lamella

  • Structural disturbances during the formation of the diamond lead to twin lamellae.
  • Kinda rare.
  • Twin lamellae are hairline-like inclusions.
internal structural features

Internal Graining - Internal structural features

  • Every diamond has internal structural features
  • Internal structural features only affect the clarity of the diamond if they are not the same color as the diamond.
  • The structural features can look like lines, angles or curves.
  • The structural features can appear white, colored or mirror-like.

Feather - feather

  • Feathers are small fractures in the diamond.
  • Large springs can affect the stability of the diamond.
  • Feathers that extend to the surface of the stone can have an impact on the stability of the stone.
with fibers

Bearded Girdle - girdle with fringes

  • Fringes are small split tears that have been caused by force.
  • The fringes extend from the girdle.
  • Fringes are an avoidable processing error and are created when the raw, angular diamond is “rubbed” into the round shape.
chip flaking

Chip - flaking

  • A shallow notch in the surface of the diamond with usually rounded edges.
  • Such chips usually occur during or after grinding and setting.

Cavity - recess

  • This recess is created because when the diamond is cut, a crystal falls out on the surface and leaves a hollow.

Indented Natural - raw crystals remaining area

  • Below the surface of the polished diamond there is a remaining area with the rough diamond surface.
  • These remaining areas are considered inclusions.
  • Cutters optimize the overall weight of the diamond by leaving such areas instead of losing more of the diamond and polishing away the remaining area.
laser drill

Laser Drill Hole - laser drilling channel

  • A tiny tunnel is drilled into the diamond using laser drilling.
  • The tunnel extends from the surface to a dark crystal, which is dissolved, colored light or made less visible by the treatment.

Grain Center

  • An area of ​​grainy crystal distortion.
  • May appear dark or light as well as thread-like and dot-like.

Knot - knot

  • Nodes are crystals that are on the surface of the cut diamond.
  • Often visible to the naked eye.


  • A notch, which is also accompanied by root-like feathers.
  • Often on the surface of the diamond.
  • It is usually reflected in the inner facets of the diamond and then appears cotton-like.

Pinpoint - needle tip, point-like inclusion

  • Tiny crystals inside a diamond.
  • They look like little dots.
  • They are mostly white, but can also be dark colored.

What blemishes occur in diamonds?

twin lines

Twin Lines - twin lines

  • Visible lines on the surface of the diamond.
  • Twin lines can cross more than one facet, whereas polish marks only occur within one facet.
raw crystal

Naturals - raw crystals remaining area

  • An unpolished remaining surface with the surface of the rough diamond.
  • Usually on or near the belt.

Scratches - scratches

  • Scratches can occur from contact with other diamonds during storage.

Abrasion - abrasion

  • Abrasions usually occur when several diamonds rub against each other. This can happen if diamonds are stored carelessly.
  • Minor indentations on an outer facet.

Pit - pits

  • Pits are tiny little cavities (recesses).
  • Pits usually look like very, very small white dots.

Nicks - notches

  • Small chips that can result from using the diamond.
  • There are usually notches around the belt.

Extra Facets - Additional facets

  • Additional facets are cut into the diamond without paying attention to symmetry.
  • Grinding additional facets removes blemishes.
  • Extra facets are not evaluated when assessing purity.

Rough Girdle

  • The surface of the belt is patchy and granular.
  • The belt appears somewhat waxy.

Burn Marks - traces of fire

  • If you grind diamonds too quickly, the friction can reach such high temperatures that the heat causes the surface to appear somewhat cloudy in some areas.
  • Such burn marks can be removed by polishing.

Kind regards, your Yorxs team

The Yorxs Magazine - always up to date on the topic of diamonds, diamond jewelry, investments and engagement. We are not just any jeweler. We want to advise our customers transparently, which is why we offer you up-to-date knowledge about jewelry and the international diamond trade.

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