With regret they are ceramic (hand made and two toned green). I have been a Sacristan for close to 10 years and have handled them (we have a matching set of four)

and can verify with certainty the material.
Let me add, I did not intend to sound negative or grumpy in my original post. I just get grumpy after a while.
To add to the topic: Our EMHC purifies the sacred vessel. With a total of 3 priests and a number of associates, assistants, and in-residence over the last 15 years, I have never witnessed a Sunday Mass where the priest purified the vessels.
I have discussed these issues with our Adult Faith Pastoral Associate (fancy title for the person who controls the sacraments) and written our current Pastor, to no benefit. I’m already risking political martyrdom and I know better to do any more than pray. Frankly, I’ve given up. I’d rather risk the abuse than having no parish to attend.