Black Spinel 4x6mm Faceted Rondelle - 15-16 Inch Spinel Sardonyx has a Sard base

Sardonyx has a Sard base

Mohs hardness 7

Green Lodolite is Quartz with inclusions of sand

Botswana Agate was formed nearly 187 million years ago by lava flowing in waves from long faults in the earth

This prompted an alternative name for the gemstone: Princess Blue

Black Spinel 4x6mm Faceted Rondelle - 15-16 Inch Spinel Sardonyx has a Sard baseSpinel is a hard vitreous magnesium aluminum oxide, and comes in a range of other colors, but those varieties are transparent. Black Spinel not only has the dark color, but it is opaque as well, rendering its black especially deep and mysterious. Sometimes called the "Black Prince's Ruby" for its role in the English crown. It has been mistaken for ruby and sapphire at times, but can be distinguished by its structure and its lower relative hardness.