*On second thought, should the "Synthetic" locality be limited to deliberately manufactured materials, or would accidental human-made things like post-mining deposits (Rocanville halite stalactites), smelter mishaps (Polish zincite), or deposits from a mine fire also qualify?

Please be very careful about the meaning and use of the terms "Man-Made", "artificial", "natural", "manufactured", "mineral", "crystalline", "amorphous", "synthetic", “growing crystals”, etc. Things are getting mixed up here! It is an extremely complex and complicated subject!

 

Günter Grundmann's points are well taken.  In an informal discussion like this it's hard to be rigorous, but it's important to keep these things in mind as the idea takes shape.

To me it would seem useful for synthetic analogs of naturally occurring minerals to appear alongside their natural counterparts for comparison, provided they are unmistakably labeled as synthetic and thus are not strictly "minerals".  Being able to attach a locality of "Synthetic" would be a clear and convenient way of doing that, maybe with standard suffixes available for clarification such as "Synthetic--laboratory" (Frank's and Pavel's crystals), "--commercially manufactured" (Carborundum crystals), "--industrial by-product" (slag minerals), and probably others.  Post-mining deposits already are generally attributed to the localities where they were found and probably should continue to be handled as they are currently.

Continuing to try to lend structure to this discussion, it sounds like there is support for allowing synthetic analogues of IMA-approved natural mineral species to appear alongside their natural counterparts with a locality designation of "Synthetic".  Although agreement is not complete, some (including me) believe that should include deliberately created materials, both laboratory and industrial, and materials created accidentally such as crystals formed in industrial glassmaking and metallurgical slag.  Post-mining deposits (including mine fire residues) would continue to appear under the localities where they were found and should be designated as "post-mining" in image captions.  "Slag minerals" formed through natural weathering of old metallurgical slags are a large grey area that would require separate discussion--let's not open that can of worms right here and now.

It has been suggested further to create a single page, perhaps in table form, of compounds appearing on the specimen market that have no IMA-approved natural mineral analogues.   The title and form of such a table are not yet clear.

Am I on the right track?

Appreciate all the input and it made me learn quite a bit from just looking over what others have added, thank you all.