You can choose any color you want. When you purchase it, there will be a place to enter the hex code of the color you want, so you can choose not only the color but the exact shade you like. Once you have formatted it, it will always be that color and if you want a different color, you'll have to buy another one. Whichever one you have active, will be the color that shows up.
I have purchased a couple now with my seashells and I love them!