Are you
IBM's Watson
I am a calculator, designer of zoos
the calculator part is fairly obvious, since watson is an AI. The zoo part, after some quick googling, it turns out that the Cincinnati zoo is using some IBM analytics stuff? That might be a stretch though.
I know many answers, yet question them too.
This could be referring to the fact that Watson is well known for having competed on the show Jeopardy, where you are given a clue in the form of an 'answer' and you must reply in the form of a 'question'. What is Watson?
I've read up on stones, red, blue, and gray.
I don't have an answer for this one, sorry
I wonder 'bout people and the things that they say.
Watson is an AI and was designed to be able to parse and understand English sentences (and maybe other languages too, but human languages, not programming languages).
My answer is clearly glaringly obvious,
So now the comes the question: I am what?
This is just referring back to the second line again, where in Jeopardy the answer comes first followed by the question.