How or When is the Lozenge symbol used?
I could find articles in Wikipedia that explain what each typographical symbol means and how it is used in print (e.g. pilcrow, section, dagger) but I couldn't find any information about the Lozenge mark/sign/symbol/character (◊ or Unicode U+25CA).
I know it's being used in modal logic and math, but is it (or has it ever been) used in English text?
Every entry of lozenge in the OED lists a heraldic, artistic, or mathematical usage.
From this we can assert that any usage in English text has, so far, been ornamental (e.g. as a list marker), or descriptive of things that incorporate the shape itself.
It's not used in text (although it could be used decoratively, in a border or as a rule or bullet). It's a mathematical symbol.