The October birthstone is the opal, a gemstone known for its unique display of colors and light. Opal is believed to bring luck and good fortune, and is thought to help bring out the best in people. Its iridescent hues of blues, greens, and reds are said to represent hope and innocence. It is also believed to bring healing powers and protection from harm. The opal is a beautiful and unique birthstone that is sure to bring joy to any October birthday.