Shabbat 21A

למאי נפקא מינה? למקח וממכר.

The Talmud asks: What is the practical difference that emerges from that which Rami bar Avin taught? The Talmud explains: Its significance is with regard to buying and selling. One who buys tar can insist upon receiving the by-product of pitch and no other material. The same is true with regard to wax and honey.

תנו רבנן: כל אלו שאמרו אין מדליקין בהן בשבת, אבל עושין מהן מדורה ⁠— בין להתחמם כנגדה בין להשתמש לאורה, בין על גבי קרקע, בין על גבי כירה. ולא אסרו אלא לעשות מהן פתילה לנר בלבד.

A baraita states in the Tosefta: With regard to all of those materials about which they said that one may not light the lamp with them on Shabbat; however, one may use them ab initio to make a bonfire. One may do so both to warm himself opposite it and to utilize its light, and he may ignite it both on the ground and on a stove. They prohibited using them only to make a wick for an oil lamp.

ולא בשמן קיק וכו׳. מאי שמן קיק? אמר שמואל: שאילתינהו לכל נחותי ימא, ואמרו לי: עוף אחד יש בכרכי הים וקיק שמו. רב יצחק בריה דרב יהודה אמר: משחא דקאזא. ריש לקיש אמר: קיקיון דיונה. אמר רבה בר בר חנה: לדידי חזי לי קיקיון דיונה, ולצלוליבא דמי ומדפשקי רבי, ועל פום חנותא מדלן יתיה, ומפרצידוהי עבדי משחא, ובענפוהי נייחן כל בריחי דמערבא.

And we learned in the Mishnah that one may not light the Shabbat lamp with kik oil. The Talmud asks: What is kik oil? Shmuel said: I asked all the seafarers, and they said to me that there is a bird in the cities on the sea coast, and kik is its name. Kik oil is produced from that bird. Rav Yitzḥak, son of Rav Yehuda, said: This is referring to cotton oil. Reish Lakish said: It is the oil made from the seed of a plant like the castor plant [kikayon] of Jonah. Rabba bar bar Ḥana said: I have seen the species of the castor plant of Jonah, and it is similar to the ricinus tree and it grows in swamps, and they place it at the entrance of shops for shade, and they produce oil from its seeds, and all the sick people of the West, Eretz Yisrael, rest beneath its branches.