How to pronounce “volcanic glass” in English

What I didn't expect was that we have water in the rocks that came up from deep inside the Moon that the astronauts picked up.In the Apollo samples, it turns out some of those samples that they brought back contained glass beads, volcanic glass beads that could protect the water inside it.And now, all these years later, we have the technology, we have the instruments to go back and analyze those samples in greater depth and differently.