Georgia O'Keeffe chiefly used charcoal for her breakthrough 1915 abstract series.
In 1915, while teaching in South Carolina, O'Keeffe made a group of highly abstract charcoal drawings. These works reduced forms to lines, curves, and areas of tonal contrast rather than depicting recognizable scenes.
She sent some of the drawings to her friend Anita Pollitzer, who showed them to Alfred Stieglitz. Stieglitz exhibited them in New York, making them among the earliest abstract works by an American woman artist to receive serious attention in that circle.
O'Keeffe later expanded her practice into oil, watercolor, pastel, and other media. The charcoal series is especially important because it marked a decisive break from academic conventions and helped define her independent visual language.