Botswana Agate has a Trigonal crystal system and is in the mineral class of oxides, the quartz group. Hot silicic acid solutions gather in hollow spaces formed by gas bubbles in cooling lava. As these solutions cool they solidify into quartz that is deposited in layers of these hollows. It’s banding comes from the deposits of other substances in the layers.
The different bands of Botswana Agate can contain several members of the Quartz family (Rock Crystal and Amethyst) with additions of the Chalcedony family (like Carnelian and Onyx), as well as many types of Jaspers. Botswana Agate is generally in shades of gray with sometimes peachy areas. It can show banding as well as solid areas of color.