Green is a green-colored crayon (also known as a wax pastel), shaded with various different shades of green. Her eyes and eyebrows are black, so are her arms, her mouth, and legs. Her tip on her head is flat.
In Time Wasters, Pink is amazed by her and Green's teamwork on making an art piece, stating how Pink's colorization of Green's line art is fabulous. Eraser Wash comes in and asks about Cap's whereabouts, to which Pink responds telling another story. Blue eventually answers Eraser Wash's question that Cap is heard giggling about climbing the bookshelf. Thanking Blue and the others, Eraser Wash storms off to said location.
Green is a very calm person, who can easily be flattered by compliments.