وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ ‏:‏ أَنَّ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ، كَتَبَ إِلَى عَامِلِهِ عَلَى دِمَشْقَ فِي الصَّدَقَةِ ‏:‏ إِنَّمَا الصَّدَقَةُ فِي الْحَرْثِ وَالْعَيْنِ وَالْمَاشِيَةِ ‏.‏ قَالَ مَالِكٌ ‏:‏ وَلاَ تَكُونُ الصَّدَقَةُ إِلاَّ فِي ثَلاَثَةِ أَشْيَاءَ ‏:‏ فِي الْحَرْثِ وَالْعَيْنِ وَالْمَاشِيَةِ ‏.‏

Yahya related to me from Malik that he had heard that Umar ibnAbd al-Aziz wrote to his governor in Damascus about zakat saying,"Zakat is paid on the produce of ploughed land, on gold and silver,and on livestock." Malik said, "Zakat is only paid on threethings: the produce of ploughed land, gold and silver, and livestock." Translation Not Available

Book reference: Muwatta Imam Malik Book 17 Hadith 583
Web reference: Muwatta Imam Malik Book 17 Hadith 3