These Turquoise stones for these studs are between 5mm - 6mm as shown. The colors range from classic TQ Blue to Blue with some Carmel matrix . All pieces are handcrafted by me, in my Arizona studio using low environmentally impacting process. The Fine Silver is nickel free and great for sensitive skin. One more quick point is the ear nuts on the Stud Earrings. They are a fancy, heavyweight ear nut and won't let you down while you are doing the Salsa or eating salsa and playing uno.