I ordered 4 rings at the same time, when they arrived i put them on and did not take them of for a week. I had them on in the shower, when washing my hands or doing dishes/cleaning. 24/7. There was no change, no turning black/green. And i am highly allergic to any metal thats not silver or gold. My skin will get red and inflammed within 24 hours when i wear non silver/gold rings. This did not happen with any of these 4 rings.
This one with the skeleton is very cool and detailed. The size is adjustable. I wear it around my ring finger which is a size 16,5 (diameter 16,5mm)/52 (circumference) /6 (us). It is stamped s925. And my opinion is that it is silver. Highly recommend!