Type 1 Gemstones

(These gemstones are typically inclusion free)

Amethyst, Beryl (except Red Beryl and Emerald), Citrine, Chrysoberyl (except Alexandrite), Garnet (except green and orange), Kunzite, Topaz, Green Tourmaline, Tanzanite, Zircon

VVS  minute to not detectable
VS     minor
SI1    NOTICEABLE to obvious
SI2    OBVIOUS to noticeable
I1      prominent to moderate affect on appearance or durability
I2      prominent to severe affect on appearance or durability
I3      prominent to severe affect on beauty, transparency, or durability

Type 2 Gemstones

(Gemstones that normally may have a few inclusions)

Alexandrite, Andalusite, Iolite, Peridot, Rhodolite, Ruby, Sapphire, Spinel, Tourmaline, and Tsavorite

VVS  minor
VS     NOTICEABLE to obvious
SI1    noticeable to OBVIOUS
SI2    obvious to prominent
I1      prominent - moderate affect on appearance or durability
I2      prominent - severe affect on appearance or durability
I3      prominent - severe affect on beauty, transparency, or durability

Type 3 Gemstones

(Gemstones that normally do not come clean)

Emerald, Red Beryl (Bixbite), and Rubellite (Red Tourmaline).

VVS  NOTICEABLE to obvious
VS     noticeable to OBVIOUS
SI1    obvious to prominent
SI2    obvious to PROMINENT
I1      prominent to considerable affect on appearance or durability
I2      prominent to severe affect on transparency or durability
I3      prominent to severe affect on beauty, transparency, or durability