Combine diamond with any gemstone to create your own unique family keepsake with the birthstones of your loved ones, or your favorite combination of colors. Diamond is known as the gem of and is the birthstone for the month of . Black Onyx is known as the gem of confidence and protection and is the birthstone for the month of December. Join these gems together to create a unique family keepsake representing the birthstones of your loved ones. You are currently viewing the items below in 14K White Gold.