Ivory Square Corozo/Tagua "Five Squares Flat Pillow" 4-Hole Button 3/4" / 18mm #SK-528
Square button with four square holes. About 1/8" thick and slightly raised - 'pillowed' in the center, and the back is flat. Buttery ivory color. Sleek, smooth, well made, unique, pretty square button is as durable as plastic but much nicer. As with most corozo buttons it light in weight but strong, with medium shine. Machine washable/dryable. $1.70 each. Panama.
Vegetable Ivory/Tagua/Corozo: Click here or here for wikipedia articles about this tropical palm tree nut. Tagua has been used for buttons since the 1880's, before plastic.