Bieber, 28, debuted a massive two-stone ring via her Instagram Story on Saturday, December 21, where a square-shaped peridot diamond sat ... makes peridot the baby's birthstone.

These stones can be worn as pendants, diamond sets, halo earrings, stud earrings, drop earrings, fashion rings, halo rings, and brooches. Tanzanite is the latest December birthstone that is said ...