These are sold by the sack. Each sack contains four 3/4" shooter marbles and four 5/8" marbles, with up to 30 colors to discover in all!
Also known as fiber optic marbles, these unique marbles are made of cat's-eye, a man-made synthetic gemstone material; however it didn't start out that way. It's a by-product of a material manufactured for the telecommunications industry - photo optic glass.
Tiny hair-like strands of pure glass are drawn from glass rods by a high-tech, fiber drawing tower. Some of the glass rods are more than a mile long and are wound on spools. The strands are used in telecommunications to make photo optic cables that transmits light signals at the speed of light over long distances.
Thousands of these hair-sized strands are pressed together under heat and pressure to form thick plates of fiber optic glass. Lapidary artisans use this special chatoyant (having a changeable luster) glass to cut and polish these marbles.
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 cables 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. Colors will vary, our choice of color please. Sold 8 marbles to a sack.