I am not a researcher on the subject, but most of the time, from my understanding, glass that appears to be opaque black is very dark blue, purple, or brownish. And what we perceive relates to the density of the glass and the amount of light that can pass through it. The outermost layer of this bead appears to be very deep blue. We can see from the edges of the ground shapes that remain of the outer layer from this image that the glass is blue. Of course, where the layer thickens and less light can pass through the bead to allow our eyes to "read" the color, it appears black. What would I call it? I'd call it deep blue, because there is no mistaking that the outermost glass is deep blue from what I can see in these images.

Large black & blue 7 layer. I guess they can be both!

THANK YOU JOYCE AND ART! THIS BEAD IS INDEED BLACK AND BLUE1 IT IS VERY INTERESTING!

I would entertain offers....

I'd call this one BLUE