Black Spinel 5x9-10x18mm Drop - 8 Inch Size_8x10-10x12mm in a variety of swirling

in a variety of swirling and linear patterns

air bubbles or black carbon deposits

the other being Diamond

phlogopite

In this strand

Black Spinel 5x9-10x18mm Drop - 8 Inch Size_8x10-10x12mm in a variety of swirlingSpinel 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.