Pack of 3. Each rock or mineral specimen measures approximately 1-2 inches in length along its longest side. Commonly distributed, Gneiss is created by the high-grade metamorphic processes from pre-existing rock formations that started out as either igneous or sedimentary rocks. Typically, gneiss is foliated, or composed of layers, with alternating light and dark colored bands, called "gneissic banding". Unlike a lot of names, gneiss actually comes from Middle High German verb gneist, rather than Latin, and means "to spark", due to its glittering nature. Origin: WY, CO, UT