I have a question. Your left turquoise bead shows black material at the bottom right. Is that part of the matrix/ natural? I have seen this in quite some beads. When it is solid as a rock I assume it is part of the matrix?

Here is a pic of a ring where a black paste seems covering a rock vein... or is it just assembled bits of turquoise or something else?
I find similar black in beads (from Nepal, genuine colour?)

I love love turquoise, but the more I know the less confident I am.
The Ladakh beads (next set of pictures) I bought beginning 90's and the sellers were emerging their beads in oil every morning, to give them a shine and make them more appealing to the customers. Unfortunately this gives them a saturated mat brownish look. It is what it is and it is part of their history now.