Black Spinel 15-20mm Double Drill Puff Hexagon - 8 Inch Stone Type_Carnelian or even multi-colored

or even multi-colored

Turquoise is one of the oldest known gemstones

ranging in color from pale yellow to golden yellow

The mineral is heavy

Gem Silica is the rarest and highest form of Chrysocolla

Black Spinel 15-20mm Double Drill Puff Hexagon - 8 Inch Stone Type_Carnelian or even multi-coloredSpinel 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.