COLORED GEMSTONE CLARITY GRADING

February 19, 2015

COLORED GEMSTONE CLARITY GRADING

CLARITY: Clarity is the second most important factor in colored gemstones.

The guidelines used for clarity in a diamonds and colored gemstones are different. Colored gemstones have more inclusions than diamonds, are not so neat, and there are certain gemstones that hardly ever appear clean.

MdMaya Gems uses the following clarity scale when grading gemstones.

Sometimes these inclusions are what make stones valuable (silks in rubies, the cat's eye effect in the alexandrite, etc.).

Setting aside translucent and opaque gemstones, the first classification to take into account is:

Type 1: Stones that are often inclusion free: Gemstones that usually don't have inclusions. Aquamarine, blue topaz, blue zircon, chrysoberyl (except alexandrite), danburite, heliodor, imperial topaz, morganite, smoky quartz, spodumene (kunzite, hiddenite), tanzanite and white zircon.

Type 2: Stones that are usually included: They usually show small inclusions that are visible to the naked eye. Apatite, alexandrite, amethyst, ametrine, corundum (sapphire and ruby), diopside, fluorite, garnets, iolite, spinel, peridot, tourmaline (except green tourmaline, rubellite, watermelon, paraiba) and zircon (red, yellow and orange). (TYPE 2)

Type 3: Stones that are almost always included: Benitoite, emerald, idocrase, kyanite, paraiba tourmaline, prehnite, red beryl, red – pink tourmaline, rubellite and watermelon tourmaline.

CLARITY GRADES:

EYE CLEAN: Appears clean to the unaided eye. (Type 1, 2 and 3)

SLIGHTLY INCLUDED:

Type 1: Minute inclusions difficult to see with the unaided eye.
Type 2: Minor inclusions easy to see with the unaided eye.
Type 3: Noticeable inclusions apparent to the unaided eye.

MODERATELY INCLUDED:

Type 1: Minor inclusions somewhat easy to see with the unaided eye.
Type 2: Noticeable inclusions apparent to the unaided eye.
Type 3: Obvious inclusions very apparent to the unaided eye.

HEAVILY included: prominent inclusions that have a negative effect on appearance or durability.

SEVERELY INCLUDED: prominent inclusions that have a severe effect on appearance or durability or both. (Type 1, 2 and 3).

A clear example: Whilst in aquamarines the term slightly means that they show really small inclusions that are very difficult for the naked eye to notice (without using a magnifying glass), when talking about emeralds slighty means notable sized inclusions that can be easily seen.