Botswana Agate 16mm A Grade Coin Cabochon Mandrel who first catalogued the stone

who first catalogued the stone in 1902

black or brown veins running through it in web-like patterns

and is a result of trace amounts of copper or chromium

and much of the black Onyx on the market has been artificially colored

each specimen will vary in size and shape

Botswana Agate 16mm A Grade Coin Cabochon Mandrel who first catalogued the stoneBotswana Agate displays highly defined parallel banding, usually in white on hues of brown, gray, pink, tan, apricot and purplish red. Botswana Agate was formed nearly 187 million years ago by lava flowing in waves from long faults in the earth. This lava rolled across the landscape, depositing layer upon layer of Quartz silicate to create the banding and patterns now prized in Botswana Agate. Sold individually. These cabochons are all unique and vary