Citrine is a variety of quartz whose color ranges from a pale yellow to brown due to ferric impurities. Natural citrines are rare; most commercial citrines are heat-treated amethysts or smoky quartzes. However, a heat-treated amethyst will have small lines in the crystal, as opposed to a natural citrine's cloudy or smokey appearance.
Brazil is the leading producer of citrine, with much of its production coming from the state of Rio Grande do Sul.
This rough comes from Kenya. It is not treated in any way. Pieces are mostly fully formed large crystals and can cut some clean and large gems.