The spelling of the word "blystone" may seem unusual at first glance, but it follows English phonetic rules. The consonant cluster "bly" represents the blend of the voiced bilabial stop /b/ and the voiced dental fricative /l/. The vowel sound in "stone" is represented by the long vowel symbol /oʊ/, which is a diphthong composed of the open back rounded vowel /o/ and the semi-vowel /ʊ/. Therefore, "blystone" is spelled as it is pronounced according to the IPA phonetic transcription.