The Messenger of Allah ﷺ threw pebbles at the jamrah using stones the size of those flicked between the fingers.
أخبرني محمد بن آدم عن عبد الرحيم عن عبيد الله بن عمر وذكر آخر عن أبي الزبير
أن رسول الله ﷺ رمى الجمرة بمثل حصى الخذف
[Sahih] Recorded by Ibn Khuzayma, no. 2875, from the hadith of Abdul-Rahim bin Sulayman through this route, and it is in al-Kubra, no. 4080, and see the following hadith.