Having made glass beads for the past 25 years, these look like glass to me. Silver and copper leaf both cause color reactions with certain colors of glass. If I were trying to replicate these beads, I would start with an offwhite or white core, roll it in copper leaf , then add opaque turquoise glass in different spots. The dark crackly area is where the copper covered off-white glass emerges between the areas of turquoise. The reddish color could be where the copper reduces on the surface and becomes red copper oxide. This can be accomplished by reducing the oxygen in the flame while making the bead. The otherwise dark appearance of the copper leaf on the off-white is the normal color of copper leaf when it has been heated into a glass surface without reduction. Reduction to copper can be spotty. So that's my take on it - if I were near my torch, I'd try to make one for you!