Is turquoise with black and white in it valuable? Any information would be appreciated. John
The black is matrix which is striking and somewhat common in certain mines such as Kingman, Sleeping Beauty, and other mines.
Most rough blocks of turquoise contain splotches or veins of the mother rock in which it formed. This can include white kaolinite which is a clay mineral. Both matrix and clay deposits can affect the color and toughness of the turquoise stone and its workability for the Native American jeweler.
In general, I would say dark matrix (black, chocolate brown, rust, gold etc.) is desirable and white inclusions, not so much because the white is associated with a more chalky consistency, therefore less tough. I’d be happy to hear the opinion of others. Paula