The varied and brilliant coloring of agate is produced by trace amounts of impurities such as copper or iron that are also brought in by groundwater. The banding seen in many agates reflects changes in the type of impurity as the process continues. Agate is found in numerous locations throughout the world. The Brazilian agates in the Jacklin Collection are considered choice specimens. The interior crystals usually consist of quartz or calcite, and sometimes consist of barite, celestite, and various sulfides.
Amethyst is the gem name given to purple quartz.
Many of the beautiful geodes in the Jacklin Collection are from Mexico. The cellular structure of bone contains many voids. Petrified dinosaur bones are found in Montana, Wyoming, Colorado, and Utah. When thin sections of the dinosaur bones are viewed through a microscope, one can see the cell structure, almost as if it were a live specimen.