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Gemstone Grading

When buying jewelry, everyone asks about the diamond grade but most people forget to consider the grade of the colored gemstones. Colored gemstones also have a grading system.

Determing the grade of a colored gemstone is actually more difficult than judging the grade of a diamond (definition). Mostly because it takes many different tools and the knowledge of how to use those tools as well as a good memory what the results of each test and how it applies to the three gemstone types. Finally, once you have determined the stones characteristics, judging how they affect the value is also more complex than with diamonds. Additionally, there is far more publicized pricing guides for diamonds than there is for colored gemstones. A great rule of thumb that I try to instill in our customers is to do your best to ask yourself, "does this stone have magic". If the answer is yes, then it is probably a decent stone.

The gemstone grading system is based on the Four Cs just like diamond grading system. Clarity, Color, Cut and Carat Weight . In my opinion, color being the most significant.

The following is a table of faceted Type I, II and III colored gemstones most often found in the marketplace:

Type I
(often inclusion free)
Type II
(Usually included)
Type III
(Almost always included)
Aquamarine Alexandrite Emerald
Quartz
(smokey)
Amethyst Tourmaline
(Red, Pink and Watermelon)
Tanzanite Citrine
Topaz
(Blue, Yellow, Orange, Pink and Red)
Corundum
(All colors)
Tourmaline
(Green)
Garnets
(All species \ variations)
Zircon
(blue)
Iolite
Peridot
Ruby
Sapphire
Tourmaline
(Blue, Orange and Yellow)
Zircon
(Green,Orange,Red and Yellow)

Type I Clarity Grades

  • VVS - Very,Very Slightly Included: Characterized by MINUTE inclusions, which are difficult to see under 10x and invisible to the unaided eye. Even under 10x, a VVS stone may at first seem to have no inclusions, only blemishes (in exceptional stones this may in fact be true).

    Typical inclusions: pinpoints, very fine needles, tiny hairline feathers, minor color zoning, very faint clouds, and percussion marks.

  • VS - Very Slightly Included: Characterized by MINOR inclusions, which are somewhat easy to see under 10x but usually invisible to the unaided eye.

    Typical inclusions: small included crystals, liquid inclusions, numerous fine needles, small fingerprints, and small feathers.

  • SI1 -SI2 - Slightly Included: Characterized by NOTICEABLE inclusions, which are apparent under 10x. In SI1 they are usually visible, and in SI2 quite visible to the unaided eye.Inclusions normally have low relief.

    Typical Inclusions: included crystals, large fingerprints, chips, feathers, considerable color zoning and dense clouds.

  • I1-I2-I3-Imperfect: Characterized by inclusions that have a negative effect on either appearance or durability, or both. In I1, there is a moderate effect on either factor; in I2, a severe effect on either factor; in I3, a severe effect on both factors. Inclusions are often large and prominent to the unaided eye, and there may be noticeable loss of transaparency.

  • Dcl-De'classe': Characterized by inclusions so numerous the entire stone is no longer transparent but translucent at best. Dcl stones lack the beauty and\or durability of faceted gemstones.

Type II Clarity Grades

  • VVS - Very,Very Slightly Included: Characterized by MINOR inclusions, which are somewhat easy to see under 10x but usually invisible to the unaided eye.

    Typical inclusions: small included crystals, liquid inclusions, fine needles, fingerprints, tiny feathers and minor color zoning.

  • VS - Very Slightly Included: Characterized by NOTICEABLE inclusions of moderate size, which are easy to see under 10x and sometimes visible to the unaided eye. Thery are still non-damaging.

    Typical inclusions: liquid inclusions, fingerprints, small chips, small feathers, moderate color zoning and clouds.

  • SI1 -SI2 - Slightly Included: Characterized by OBVIOUS inclusions, which are large and/ or numerous under 10x. In SI1 they are apparent, and in SI2 very apparent to the unaided eye.

    Typical Inclusions:large included crystals, moderate feathers, large chips, considerable color zoning and dense clouds.

  • I1-I2-I3-Imperfect: Characterized by inclusions that may have a negative effect on either appearance or durability or both. In I1 there is moderate effect on either factor; In I2 a severe effect on either factor; In I3 a severe effect on both factors. Inclusions are often large and prominent to the unaided eye and there may be noticeable loss of transparency.

  • Dcl-De'classe': Characterized by inclusions so numerous the entire stone is no longer transparent but translucent at best. Dcl stones lack the beauty and\or durability of faceted gemstones.

Type III Clarity Grades

  • VVS - Very,Very Slightly Included: Characterized by NOTICEABLE inclusions, which are easy to see under 10x but usually invisible to the unaided eye.

    Typical inclusions: small included crystals, liquid inclusions, fine needles and tiny feathers.

  • VS - Very Slightly Included: Characterized by OBVIOUS inclusions which are very easy to see under 10x and are often visible to the unaided eye.

    Typical inclusions: liquid inclusions, fingerprints, chips and small feathers.

  • SI1 -SI2 - Slightly Included: Characterized by PROMINENT inclusions, which are large and numerous under 10x. In SI1 they are prominent and in SI2 very prominent to the unaided eye.

    Typical Inclusions:easily visible but not extensive feathers and dense clouds.

  • I1-I2-I3-Imperfect: Characterized by inclusions that have a negative effect on appearance or durability, or both. In I1 there is a moderate effect on either factor; in I2 a severe effect on either factor; in I3 a severe effect on both factors. Inclusions are often large and prominent to the unaided eye and there may be noticeable loss of transparency.

  • Dcl-De'classe': Characterized by inclusions so numerous the entire stone is no longer transparent but translucent at best. Dcl stones lack the beauty and\or durability of faceted gemstones.

As you can see colored gemstone grading is slightly more difficult than Diamond grading.

Just try to avoid colored (or uncolored for that matter) gemstones with large black inclusions that detract from the stones beauty. For the most part, use your common sense. You know in your heart when you are looking at a nicely colored gemstone. If you have to ask yourself, then you probably are not!