Now, what is the difference between a rock and a stone? Both use the vowel ‘o’ (short in ‘rock,’ long in ‘stone’), both are words of one syllable, and there the similarity ends. ‘Stone’ has a mute near the beginning of the word that then is softened by a vowel. ‘Rock’ ends with the mute ‘k.’ That ‘k’ “suddenly stops the breath.” There is a seed of silence at the edge of the sound. Brief though it is, it is definite, and cannot be denied, and it feels very different from the ‘-one’ ending of ‘stone.’ In my mind’s eye I see the weather-softened roundness of stone, the juts and angled edges of rock.
Mary Oliver, A Poetry Handbook. (I am only four chapters in and I think just about every aspiring writer, poet or not, should read this. The above quote barely scratches the surface.)