Georgia O'Keeffe used charcoal for the 1915 drawings that established her abstract style.
In 1915, O'Keeffe produced a series of boldly simplified charcoal drawings while teaching in South Carolina. These works reduced landscapes and natural forms to dynamic lines, shapes, and tonal contrasts rather than depicting recognizable scenes in a conventional way.
The drawings were a major turning point because they demonstrated that O'Keeffe could create powerful art without relying on detailed representation. She mailed some of them to her friend and former classmate Anita Pollitzer, who showed them to Alfred Stieglitz.
Stieglitz exhibited the drawings in New York, helping launch O'Keeffe’s professional career. The charcoal series is often discussed as an early landmark of American abstraction, not merely as preparatory sketching.