What is the natural source of ametrine?

Ametrine, a captivating gemstone that is a combination of amethyst and citrine, primarily derives its natural source from Bolivia. The most notable deposits are found in the Anahi mine located in the eastern part of the country. This mine is renowned for producing high-quality ametrine gemstones, often showcasing distinct color zoning where the purple hues of amethyst transition into the golden yellows of citrine.

While Brazil is also known for producing various colored stones, including amethyst and citrine, it does not have a significant source of natural ametrine like Bolivia does. Argentina and India have some deposits of amethyst and citrine, but they are not recognized for ametrine production. Thus, the prominence of Bolivia in the production of this unique gemstone makes it the correct answer.