This is an incredible find! - a 10k yellow gold baby ring with a Persian turquoise, still in its original velvet lined cardboard presentation box. If you have a new grandchild, and are looking for a really special, one-of-a-kind gift, then this is surely it. Made in the 1870's-1880's, it has a wonderful Victorian design, and is hallmarked 10k and OB for the jewelry firm of Ostby & Barton of Providence RI, who was the largest producer of gold rings in that era. The size of this ring is smaller than any even .5, so I will call it .3, but it measures exactly 12mm in diameter which is approximately 1/2". It is in like new condition and has not been cleaned or polished. The box is even in excellent condition.