TM salt??

["marilyn wiese" <marilynwiese@prodigy.net>]

I have seen the product TM salt (?) mentioned several times on this list.
What is it and where is it purchased?  We have a pink colored mineral salt
block out for our horses, they have had it for over a year and most of it is
still there (our climate is dry and hot......not humid and these guys are
young so have not been worked much or hard at all).  I have seen mention of
free choice minerals and salt (loose) but am not quite sure what it is or
where to get it.  Please enlighten me  :)

Thanks, Marilyn, Khal and Scout in San Angelo, TX