Botswana Agate 18-25x30-44mm AAA Grade Medium Free Form Cabochon Brazilian Selenite is a crystal formed

Selenite is a crystal formed from the mineral gypsum

Black Opal is a naturally occurring variety of precious opal mined in Australia

It is a potent combination of these minerals

in Karelia

but has been used historically to describe the transparent variety

Botswana Agate 18-25x30-44mm AAA Grade Medium Free Form Cabochon Brazilian Selenite is a crystal formedBotswana 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