(Priced by origin, cut, size, clarity, COLOR and rareness of material)The main factor to take into account when valuing an Amethyst is color. Amethysts that have the color of weak, grape kool-aid are inexpensive, and not very attractive.
Some of the finest Amethyst used to come from Siberia, Russia. It was prized by royalty and was deep purple with a slight blue hue and sparks of red would appear randomly. Unfortunately, this material has been mined out.
Brazil will occasionally produce a rare super saturated bright purple with no secondary hues but only rarely. Most Brazilian Amethyst material does not contain the blue hue, nor the red flash and is lighter than Siberian Quality material.
Top -quality Uruguay Amethyst which is deep purple, usually flawless, has the underlying blue hue and sparks in red like the finest Siberian Amethysts is expensive and getting scarce. Uruguayan material is disappearing like the Siberian material from Russia. We bought the best of the best several years ago but now have to buy it gem by gem, as it appears. The geodes are being swept up for use in natural rough form in top hotels, homes and offices around the world. Supplies have also dwindled.
4-Peaks mine (Arizona) was mined out due to over-mining by China and is primarily a museum now. Some of the new African Material is very dark purple, sometimes too dark or muddy, and frequently is treated with heat or radiation. But when we find natural top material can be very nice.
Brazil except for the rare, vivid, saturated purple with no secondary hues/tones is not as desirable as Uruguayan material. It sells for much less amd is commercial grade.
MOST DESIRABLE - Deep Purple, Slight Blue Hue, Flawless Clarity, Rare Red Flash. Precision Cut. Known In The Trade as, “Siberian Quality.” Only Uruguay is producing this red-flash quality untreated by heat, or radiation currently. A gem that appears to have red burning-embers inside the gem is the finest available material.
As WORLD supplies dwindle of the Uruguay material prices will likely rise dramatically in price.