Stone is also a term that has come into use to describe how serious someone is in a particular interest, orientation, or group. To be a "Stone ______" is to be a
fanatic, a serious practitioner, and someone who could be a
poster child for whatever the
rubric one could use to describe said person. The term carries the implication of permanence, of solidity and unwavering passion, someone literally "cut out" for their position, interest, or orientation.
It is a very flexible word, and can be used in many ways. For example, stone cold is pretty damn cold (as is stone dead), and a stone butch is about as far from a female as you can get and still have a vagina. Someone stone deaf can't appreciate music without a hearing aid, and stone free is what Jimmy Hendrix sang about.
This is of course related to the many other terms using stone. Things can be written or carved into stone (in a literal or figurative sense), a stony expression is certainly unkind, and to be stoned is either a very good or a very bad thing to have happen to you.