Geology Rocks Science T-Shirt Solid colors: 100% Cotton; Heather Grey: 90% Cotton, 10% Polyester; All Other Heathers: 50% Cotton, 50% Polyester Imported Machine wash cold with like colors, dry low heat This is a great gift for any scientist, nerd or geologist teacher This a funny shirt for any lover of science or rocks Lightweight, Classic fit, Double-needle sleeve and bottom hem