Ametrine is Not What it Used to Be!...
The word/term Ametrine is a contraction of Amethyst-Citrine, where Amethyst is purple and Citrine is a gold or yellow. The material comes from only one place in the world - Bolivia, not far from the Brasilian border. The material coming out of this one mine (Anahi), can be just Citrine, just Amethyst or a combination of the two - Ametrine. Cutting a gemstone with the two colors will produce a gem that one can call Ametrine.
There are various grades of this material also, just like all gemstones. We still have some incredible material purchased in the very early 1980s while on a gemstone purchasing trip in Brasil. These gems are a deep purple and deep yellow. This is in keeping with what All That Glitters seeks to place into inventory - gems that are unique, rare or unusual for that species, in this case, a nice deep rich color for both the purple and the yellow. The typical Ametrine that one usually sees on the market, especially on tv, is the very pale material - so pale at times, that one must hold it against a white background to observe the color. This more common material is the cheapest material in Ametrine.
Some people/businesses selling the 'off' color "Ametrine" are also indicating that it is from Bolivia and natural. A few have stated that it has been irradiated or at least treated in some way. One thing that we can say for sure is that this is NOT Ametrine, and it is not natural color. It could be natural Quartz, but some process has been applied to create two distinct colors - so all this being said, the color is not natural. The sad thing about this is that the term Ametrine is being applied to these 'gems'. This helps to confuse the retail customer only more with confusing terminology, various treatments, synthetics and simulants! The only way that anyone should be selling it as naturally coming from Bolivia, is that the quartz was mined in Bolivia (and then it was treated). That would be the closest one can come to natural Bolivian origin!
I am also afraid that these same dealers who have these off color Ametrines, also has some deeper colored purple and yellow faceted gemstones, (and this can certainly be called Ametrine). Is it natural color or perhaps even lab grown or irradiated material? Having been familiar with these material for over 30 years and knowing about the saturation of color, I would say that these too have been treated.
For those purchasing the off color Ametrines, be aware - this is not Ametrine and the color is highly suspicious. I would also caution those purchasing fine colored Ametrine (or even a medium color or perhaps even any color of purple/yellow Ametrine), that the gemstone might not be a true Ametrine from the Anahi Mine in Bolivia. I would feel far more comfortable in purchasing from dealers I know, have known for decades, as well as those that I know purchase rough directly from the mine owners, versus these companies (mostly outside of the U.S.) that have an Ametrine of even the expected color, but who also sell the blue/green, yellow/blue, orange/blue and all the other variations.
Since our material was purchased decades ago, we at least know that there is nothing unusual with the color and that it is natural. Enjoy the World of Gemstones and gemstone buying, but be suspicious at times when something very unusual comes along AND one is seeing it in quantity - a similar situation to the recent diffused Andesine Feldspar story....