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diamonds clarity grading scale

Virtually all natural diamonds contain identifying characteristics, many of which are invisible to the naked eye.
Clarity is the degree to which a stone is free from marks called blemishes and internal features called inclusions.
Inclusions normally have a greater impact on grade, value, beauty, and durability than do blemishes.

Imperfections on the outside of a diamond

Chip: A little piece missing, caused by wear or the cutting process. Scratch: A line or abrasion.
Fracture: A crack on the diamond's surface.
Polishing lines: Fine lines on the stone's surface formed during the polishing stage.
Natural: An unpolished part of the diamond.
Extra facets: Additional polished surfaces that shouldn't be there and spoil the symmetry of a diamond.
Bearding: Very small fractures on an edge of the diamond.

Imperfections inside a diamond.

Carbon: Black spots inside a stone.
Feather: Internal cracking.
Crystal: White spots inside a stone.
Pinpoint: Tiny spots, smaller than a crystal.
Cloud: A group of pinpoints, which may give the impression of a single large inclusion.

All clarity grading is performed at 10X magnification using a hand loupe or gemological microscope under both artificial daylight and darkfield illumination conditions. Reflected light is used to detect and evaluate blemishes and darkfield light for inclusions. It's the face-up view that usually sets the clarity grade, however the face-up, pavilion and table-to-culet views are all taken into consideration during grading. Clarity grades are largely determined by the collective visual appearance that a stone's inclusions exhibit in relationship to the size and shape of the stone. It is the consideration of the size, position, number, color/contrast and nature of these inclusions, which leads to the final clarity grade.

Clarity grades of diamonds, as established by the Gemological Institute of America (GIA):

Flawless Free from all blemishes, or inclusions.
Very rare and very expensive.
Internally Flawless No inclusions visible at 10x magnification.
Also very rare and very expensive.
Very Very Slightly Included #1 Inclusions that are extremely difficult to detect at 10x.
Rare and expensive.
Very Very Slightly Included #2 Inclusions that are very difficult to detect at 10x.
Very Slightly Included #1 Minor inclusions, difficult to detect at 10x.
Very Slightly Included #2 Minor inclusions, somewhat difficult to detect at 10x.
Slightly Included #1 Noticeable inclusions, easy to detect at 10x.
Good quality.
Slightly Included #2 Noticeable inclusions, very easy to detect at 10x.
Slightly Included #3 Some inclusions may be seen with the unaided eye.
Included (imperfect) #1 Obvious inclusions. Somewhat easy to detect with the unaided eye.
Commercial grade.
Included (imperfect) #2 Obvious inclusions. Easy to locate with the unaided eye.
Included (imperfect) #3 Obvious inclusions. Very easy to detect with the unaided eye.
Not a pretty diamond.

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