Under intense light, my beads have a slightly translucent cobalt outer layer and an opaque inner layer that looks almost black. On one bead, the outer layer is quite pale compared to the others. But I have only 6 of these in my collection so it's a small sample.

I have seen a lot of variation in the opacity of dark cobalt blue beads of all types. In some cases it is easy to tell that the color is blue and in other cases, it is opaque and looks almost black, unless lit with a really strong light. So my suggestion is that both of your beads are old, just not identical.