Interesting to see Mother of Pearl used in connection with this Kralik range, both capitalised and abbreviated. I use mother of pearl uncapitalised and unabbreviated in connection with a similar range of iridescent non-airtrap fancy glass by Walsh, with the authority of Leibe/Hayhurst, Miller's Glass of the '20s & '30s
, 1999, p22. In the Walsh context, I would only capitalise it if I had evidence of Walsh use of the term. I would never abbreviate it to MOP or MoP as unfortunately this is now standard collector terminology for airtrap, particularly in the US.
What is the term's status in respect of this Kralik range?
... and thanks. I thought that this range was by Loetz! You never stop learning.