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Clarity in gemstones


‘Eye clean’ clarity in danburite — specimen 0502
‘Eye clean’ clarity in danburite — specimen 0502, photo © NMNHS
The clarity is another important characteristics when evaluating gemstones. We use the grading scheme shown below.

Clarity grades in diamonds

FL

Flawless. Have no inclusions or blemishes visible under a loupe with 10 times magnification. Perfect quality.

IF

Internally flawless. Loupe clean; free of inclusions. These gems have microscopic inclusions which are difficult to see under a loupe with 10 times magnification. Extra fine quality.

VVS1

Very very slightly included 1. Almost loupe clean; very, very slight inclusions. Inclusions barely seen under 10 times magnification. However, the beauty of the gem is not diminished in anyway. VVS1 denotes a higher clarity grade than VVS2. Pinpoints and needles set the grade at VVS. Very fine quality.

VVS2

Very very slightly included 2. Almost loupe clean; very, very slight inclusions. Inclusions barely seen under 10 times magnification. However, the beauty of the gem is not diminished in anyway. VVS2 denotes a lower clarity grade than VVS1. Pinpoints and needles set the grade at VVS. Very fine quality.

VS1

Very slightly included 1. Eye clean; very slight inclusions. Inclusions can be seen under 10 times magnification. However, the overall beauty of the gem is still not diminished. VS1 denotes a higher clarity grade than VS2. Fine quality.

VS2

Very slightly included 2. Eye clean; very slight inclusions. Inclusions can be seen under 10 times magnification. However, the overall beauty of the gem is still not diminished. VS2 denotes a lower clarity grade than VS1. Infrequently some VS2 inclusions may still be visible to the naked eye. Fine quality.

SI1

Slightly included 1. These gems have small inclusions which can be seen under the close naked eye. These inclusions are usually not really visible at an arm's length. SI1 denotes a higher clarity grade than SI2. Good to medium-high quality.

SI2

Slightly included 2. These gems have small inclusions which can be seen under the close naked eye. These inclusions are usually not really visible at an arm's length. SI2 denotes a lower clarity grade than SI1. Good to medium-high quality.

I1

Included 1. Included gems with internal features that range from eye visible to very easily seen to the naked eye. I1 denotes a higher clarity grade than I1 and I3. Medium to the lower qualities.

I2

Included 2. Included gems with internal features that range from eye visible to very easily seen to the naked eye. I2 denotes a lower clarity grade than I1 and higher than I3. Medium to the lower qualities.

I3

Included 3. Included gems with internal features that range from eye visible to very easily seen to the naked eye. I3 denotes a lower clarity grade than I1 and I2. Medium to the lower qualities.

Clarity grades in coloured stones

eye clean

Appears clean to the unaided eye.

slightly included

Minor inclusions somewhat easy to see with the unaided eye.

moderately included

Noticeable inclusions apparent to the unaided eye.

heavily included

Prominent inclusions that have a negative effect on either appearance, or durability.

severely included

Prominent inclusions that have a severe effect on appearance, durability, or both.

Clarity grades in cabochons, opaque stones

translucent

Allow light to pass through, can be heavily included. Some gems are naturally translucent.

opaque

Does not allow light to pass through, highly included. Some gems are naturally opaque.