Sterling Silver Graduated Diamond Stud Earrings

Sterling silver stud earrings set with graduated diamonds. Stones test in diamond range on my presidium gem tester. I do not know if these are natural or lab created. Earrings measure 5/8ths of an inch length and approx. 3mm at widest point at the top. There are tiny stamps that can be read with a loupe on the posts that say S925, D 0.43ct. Earrings acid test positive for sterling silver. O