Millipede Conch shells are known for their unique spikes which compare to the insect they are named after. Millipede conch are off-white in color with shades of brown, pink and yellow. These sliced millipede shells are often used for crafts and display the unique inner-makings of the seashell. Conch seashells of any kind can be used to decorate any room of your home or beach cottage. Each sliced shell measures approximately 3 inches.