These viintage buttons are 1 1/8" in diameter. They have two holes for fastening to your creation.
They are more than likely plastic. Darker brown in the center with the sides/edgeges on two sides a lighter brown color. I don't know if you can see it clearly in the pics.
Still attached to the original cardboard card. The card is creased and worn. Has a part number oc initial "C" in a circle and number 108. Made in the U.S. Chic Buttons - you can barely see the name under the hole punched in the card for hanging.