Agate is a banded form of chalcedony i.e. a non / minute crystalline variety of silica, belonging to the quartz family of minerals. The slices have been died purple, pink or blue which makes for particularly attractive and eye catching specimens, enhancing the banding of each slice. We also have some natural brown slices which have not been died if you prefer a more authentic product. These agate slices started life as gas bubbles within lava. Over time silica rich volcanic fluids filled these empty cavities which eventually solidified; the bands represent different growth phases. Once exposed at the surface the solid agate has been sliced and polished. These specimens measure between 4 and 6 cm in Length / diameter and are supplied in a tightly sealed blister pack. The pack comes with a detailed information card and a plastic hand lens to enhance the viewing of the sample. An ideal gift for children, beginner geologists and collectors.