I found Parisian nacre opera glasses in a drawer while looking for something else and threw them on the mantel along with my c. 1905 Manuel Garcia relic which has a 'new' 1850's frame, a Head of a Youth from the Metropolitan Museum of Art, and brain coral. I like how the coral echoes the Youth's hair.
Ok. I can't remember the last time I used the word nacre, but it seems that Wikipedia is trying to educate us. That's the word that comes up when you google "mother of pearl."
If only those opera glasses were magical and could look into the past. I'd focus them on my relic and peer back in time to see the great maestro at work in his studio. That's where my head is at right now: long dead singing teachers and their means and methods.