Size is as-packaged, or the diameter of loose marbles. ("D" is the diameter of round items other than marbles.)
To make these, thousands of hair-thin fiber optic glass strands are compressed under heat and pressure to form thick plates of
fiber optic glass. Also known as cat's-eye (a man-made synthetic gemstone), this special chatoyant (having a changeable
luster) glass is cut and polished to make these spheres.
With a magnifying glass, you can see the individual ends of the fibers (examine the side
of the marble light passes through.) Because fiber optic strands transmit light, if you place that side down on
print, the image of the text is transmitted through the marble, and appears to be printed on the top surface! A
beautiful tiger-eye effect is seen when the marble is viewed from any other angle.