Black Spinel 8mm Round - 15-16 Inch Turkey second only to Quartz

second only to Quartz

They are all varieties of the mineral corundum

African Turquoise is not actually Turquoise

Green is the most common color for Aventurine

The most precious Fire Opal has flashes of iridescence and is known as Precious Fire Opal or “Firmament Stone

Black Spinel 8mm Round - 15-16 Inch Turkey second only to QuartzSpinel 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.