Botswana Agate

According to a University of Botswana study, Botswana agates are found mainly in the Bobonong area of the Central District in north-eastern Botswana, along the Motloutse River, and around Serowe to the south-west, with smaller amounts near Mahalapye and Kanye. The host rock is basalt of the 180-million-year-old Karoo volcanics. Most are small wall-lining nodules coated with green clay (identified as celadonite); vein agates are less common. After the rainy season, loose agates weathered out of the basalt litter the fields along the river. The study cites an export of about 48 tonnes of polished agate per year.

Mindat characterises Botswana agate by fine, parallel banding, often pink blending into white. Rough nodules typically carry a green-earth (celadonite) coating. As agate it gives the chalcedony readings (refractive index about 1.53–1.54, specific gravity about 2.6). The so-called "green moss agate" or "gorgonzola" from the same Bobonong area is, according to the University of Botswana study, granular microcrystalline quartz rather than agate. Agate is commonly dyed; unnatural, vivid colours indicate dye.

Agate is durable (hardness about 7) and can be washed with warm water and a mild dish soap, then dried. If a bead may be dyed, avoid steam, ultrasonic cleaners, heat and solvents, which GIA notes can affect treated gems.

The Japanese retailer Pascle associates Botswana agate, like other agate and chalcedony, with sharing and good relationships, and says it is traditionally said to strengthen fertility, making it a popular charm for conception and safe childbirth in Japan's crystal trade. These are retail traditions, not verified properties.