Tanzanite:

Tanzanite is the exquisite blue variety of the mineral Zoisite that is only found in one part of the world. Named for its limited geographic origin in Tanzania, tanzanite has quickly risen to popularity since its relatively recent discovery. Ancient Maasai tribes of Tanzania believe the stone to contain properties that allow for a quick but gentle connection to angelic realms. Tanzanite is also believed to have healing properties and protect its wearer from dangers.

Blue zircon:

Zircon, another modern birthstone associated with December can be found in various amounts of colours. Although blue Zircon is the most traditional colour for a December birthstone, the yellow, brown and pinkish/ brown varieties may also be used.  Zircon is believed to relieve body pains and increase one’s appetite.