This birthstone of October embodies the orange and red colors of a warming fire. The fiery sparkle of this gem makes a fire opal ring become the center of conversation Tanzanite is the new birthstone of December and has a unique purple-blue color. A tanzanite ring is one of the newest fashion trends and is a must for any jewelry collection. Sapphire is the birthstone of September, and pink sapphire is a very popular gemstone in jewelry today. The bright and happy color of a pink sapphire ring is both playful and trendy.