From Automic Gold website: Vibrant color, minimalist design, these tanzanite earrings are the perfect gemstone jewelry pieces. Wear these delicate solid gold studs whenever and wherever. Dimensions Stone diameter is 3mm Item Weight Approximately 0.6g per pair with standard pushbacks Post Pushback posts are 0.75mm thick (~20 gauge). Screwback posts are 1mm thick (~18 gauge). All posts are 9.5mm long Backs Comes with 14k backings Stone Natural tanzanite. Natural stones may vary in color