Blue Lobster, Homarus americanus An estimated one in two million Northern Lobsters are blue. This is due to a random genetic variation which produces the blue pigment. These large 5" x 7" high quality art cards are printed on card stock, come pre-folded, packed in a clear sleeve per 10 cards, and include one white envelope for each card. Cards are blank inside for a personalized message. Printed on recycled paper.