1.4" Dravite Crystal - St. Lawrence County, NY

Dravite, also known as "brown tourmaline," is composed of sodium, magnesium, aluminum, and boro-silicate, with the chemical formula of NaMg3Al6(BO3)3Si6O18(OH)3F. Dravite is a subclass of tourmaline, which along with schorl tourmaline and uvite (also subclasses of tourmaline), form into a prismatic/columnar formation.

This prismatic structure can be seen on this dravite specimen, where one side shows its prismatic shape, and the other rough side shows where it grew against another mineral.