What Is Tourmaline? A Mineral Family, Not One Stone

Tourmaline isn't a single mineral — it's a complex group of chemically related borosilicate minerals, which is why it occurs in more colors than almost any other gemstone. Iron tends to produce greens and blues; manganese produces pinks and reds. Because a single crystal can shift chemistry as it grows, some specimens show multiple colors in one stone — "watermelon tourmaline," with a pink core and green outer rim, is the best-known example.

Major sources include Brazil (historically the source of the most vivid blue-green "Paraíba" material), along with Nigeria and Afghanistan, both significant producers of a wide range of tourmaline colors today.