Protecting patina

Hello All, I have been putting a patina on dapped circles with my
torch and using them in earrings. I love the way the patina turns
out because it is not controled. I have been selling the earrings,
but I am not sure about the longevity of the patina. I would like to
coat it with something to ensure that it will last.

Any ideas?
Thank you!
Ann Madland