Tractate Shabbat - Chapter 8 - Mishnah 5 שבת פרק ח׳ משנה ה׳

Red earth, as much as is required for a seal on merchandise bags, the words of Rabbi Akiva. But the sages say: as much as is required for the seal on letters. Manure, or thin sand, as much as is required for fertilizing a cabbage stalk, the words of Rabbi Akiva. But the sages say: for fertilizing one leek plant. Thick sand, as much as is required for putting on a full plaster trowel. Reed, as much as is required for making a pen. But if it is thick or crushed, as much as is required for boiling the lightest of eggs beaten up and placed in a stew pot.