For sale, a rare and vintage Sterling Silver ring from Mexico with a mystery Stone. Size: 5.5 Weight: 6.2 Grams Hallmarks: 925 (92.5% silver content) Gemstone: I just made the name up "Rainbow / Marble Quartz". Oval in shape, measuring 14 mm long x 11 mm wide. It is a clear, partly see-through stone with obvious colorful lines through it of blue, green and pink. I could not find a similar gemstone on the internet. I do think it is Quartz. Band width: 3.5 mm This is a gorgeous ring, rare and handmade vintage. Perfect as a gift or for yourself. Made in Mexico.