ðə ɹˈɑːk ɪtsˈɛlf lˈaɪz ɐpɹˈɑːksɪmətli nˈɔːɹθ ʌvðə nˈɔːɹðɚn mˈɑːɹdʒɪn ʌvðə sənt ˈɔːstɛl ɡɹˈænɪt, wˌɪtʃ ɪz ðə smˈɔːlɪst ʌvðə fˈaɪv mˈeɪn ɐpˈɑːfaɪzᵻz ʌvðə hɜːsˈɪniən bˈæθəlˌɪθ ʌv saʊθwˈɛst ˈɪŋɡlənd.
The Rock itself lies  approximately  north of the northern margin of the St Austell granite, which is the smallest of the five main apophyses of the Hercynian batholith of Southwest England.