Kingman Turquoise 6mm Blue Brown Rondelle - 15-16 Inch R0301 and this can be confirmed

and this can be confirmed under magnification

black with a golden sheen

The Ruby inclusions in this stone are pink to reddish purple to dark purple

It may also contain rainbow to colored or sparkling inclusions

black or yellow

Kingman Turquoise 6mm Blue Brown Rondelle - 15-16 Inch R0301 and this can be confirmedKingman turquoise, mined in the Acerbate Mountains near Kingman, Arizona, is renowned for its vibrant, intense blue hues, often featuring a black, "water web" matrix. Operated by the Colbaugh family, the mine is one of the largest and oldest producers of American turquoise, famous for producing nuggets in a wide color range from pale blue to dark green.