This “sand” is actually not sand at all. Rather than rock fragments, it is made of tiny, star-shaped fossils. Each piece is a fossilized exoskeleton of a sea creature from the Foraminifera group. These amoeba-like organisms have existed for about 542 million years, and over 50,000 species are known. Their innumerable remains can be found on some beaches, but only a few beaches in the world are made of star sand. This particular sample is from Ishigaki Island in Okinawa, Japan. Okinawan star sand displayed in a round acrylic case.  Be sure to check them out under magnification. Container Dimensions: 1.75" x .25"   Beach photo is of Ishagaki Island by Christoph Schmid