These pretty Dichroic post earring would make a wonderful gift. The diameters are approx. 5/16 -3/8 inch round. They are mounted on silver surgical stainless steel flat pad post stud with silver surgical stainless steel butterfly backs or plastic ear nuts. Each pair of earring is on a 3.5 x 2 card. Since glass working is not an exact science, some small imperfections may be appear on the glass. Each pair is hand made and no two will look alike. Dichroic glass is glass which can display multiple different colors depending on lighting conditions. The earrings come in a box for gift giving.