The Fancy size marble is approx 0.55" or 14mm. They include translucent and opaque marbles of 30 colors! This size has all the elegance of the smaller marbles, lots of jewel toned color choices and is big enough to make a large splash of color. Marbles include red, orange, yellow, green, blue, black, white; translucents and opaques, cats eyes and iridescents. Buy some semi-precious gemstones or "gem marbles" to add even more options to your marble collection!