It is recommended to kiss the black stone during circumambulation (Tawaf)
وَحَدَّثَنِيهِ مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا عَبْدُ الرَّحْمَنِ، عَنْ سُفْيَانَ، بِهَذَا الإِسْنَادِ قَالَ وَلَكِنِّي رَأَيْتُ أَبَا الْقَاسِمِ صلى الله عليه وسلم بِكَ حَفِيًّا . وَلَمْ يَقُلْ وَالْتَزَمَهُ .
This hadith has been narrated on the authority of Sufyan with the same chain of transmitters (and the words are):" That he ('Umar) said: But I saw Abu'l-Qasim (way peace be upon him) having great love for you." And he did not mention about clinging to it.