This fourth article in the author's series on the pegmatite districts of Minas Gerais, Brazil, focuses on chrysoberyl, particularly the rare but coveted varieties cat's-eye and alexandrite. Most of the cat’s-eye chrysoberyls on the gem market today come from Brazil, primarily from the region around the Americana and Santana valleys. This article examines some of the more important mines in this region, with a detailed description of the Barro Preto deposit. Farther south, the Malacacheta area has produced a number of fine alexandrites during the last 13 years. Since October 1986, however, it has been overshadowed in both quality and quantity by the small Lavra de Hematita, which produced 50 kg of fine alexandrite in less than three months. These two occurrences are also described in detail.