Unfortunately, gem traders often give minerals nick or trade names.
For example Padparadscha, Tanzanite or nonsense like Demantoid Garnet.



Trade names, perhaps. but silly or nonsense? The three you've mentioned
are
among the most legitimately recognized such names, well accepted by the
gemmological community and in use for a significant time, each describing
a well
known and defined gem, well understood as exactly what they are, at least
for
the second two.

I didn't say silly, -- I said trade names. And by nonsense, I meant that if
there
any logic in the Demantoid Garnet name, perhaps Ruby Spinel could be
considered as a legitimate name.

Some confusion can exist in just which colors constitute a
Padparadsha sapphire, but certainly the gemological community and jewelry
industry has little trouble with any of these three.

Actually, there are a lot of confusion with "Padparadsha":
http://www.padparadscha.info/No1/page1.htm

Now, if you want misleading names, nicknames, and the like which really do
deserve to be used with the word "unfortunately", try "precious topaz",
"smokey
topaz" "Mystic topaz" "Pigeon blood ruby", or terms like that, which can
be
misleading, confusing, just plain wrong, or at least so loosely or
subjectively
defined as to be not very useful in real communication

Agreed.

Best Regards
Andrei Vesselovski