Amethyst is the gem that’s most associated with the colour purple, although there are other purple gems, like sapphire and tanzanite. The finest amethyst colour is a strong reddish purple or purple, with no visible colour zoning.
The first grade includes the best amethysts. They’re a vivid, medium-dark to dark reddish purple or purple, and the best of them have no visible face-up colour zoning. This grade might be described as “super,” “extra,” or “AAA.” Some dealers also use “African” or “Zambian” for this grade.
Gems in the second grade are a little less saturated in colour. Although they’re attractive, some might show face-up colour zoning. Or they might be slightly included. Dealers often call calibrated amethysts in this grade “medium-dark,” “AA” or “A”.
The third grade is considerably lighter in tone and saturation than the better ones – a light lilac rather than an intense purple. Gems in this grade are popular in mass-market jewelry, and they’re usually much less expensive than more intensely coloured goods. Dealers might call them “B” or “medium.”
The fourth and lowest grade is lighter still, and not very attractive. Hues are less saturated, so they take on a grayish to slightly grayish pale purple colour. Stones with a brownish tint are even less marketable. Gems in this grade tends to be low in value. Dealers often call them “light” or “C”.
Courtesy: GIA. Resource: Amanda. #eClarity