Clark: 7mm, 2.5ct Brilliant Cut Ice on Fire CZ Screw-back Stud Earrings 925 Sterling Silver, 3121A Hard-to-find threaded posts with screw-on backs available in sizes from 3mm to 10mm! Features the outstanding fire, sparkle and clarity of Russian Ice on Fire CZ's! A great choice for men and women alike (unisex design)! Made with solid 925 Sterling Silver.