Black Spinel 4x8mm Faceted Rondelle - 15-16 Inch R1339 Aquamarine is a transparent to

Aquamarine is a transparent to translucent stone ranging from cerulean blue to light blue in higher grades

It can even exhibit various colors within the same specimen

Specialists soak the stones in resin or liquid plastic to help harden them

but also for industrial purposes from watch gears and scientific instruments to sandpaper and other abrasives

There is another form of Peridot that is not even native to the planet

Black Spinel 4x8mm Faceted Rondelle - 15-16 Inch R1339 Aquamarine is a transparent toSpinel 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.