I like that too . . .
My basis is still "is it a pretty marble?" although I occasionally digress to get something of historical interest, to me if to no one else. Or to get a type I feel I should have, even if I don't find it to be particularly beautiful. And I'm lucky enough to have a very few rare ones -- not all of which are beautiful. But in general, the "buy what you like" philosophy has held up pretty well for me over the years . . .