As we discussed on yesterday’s daf, the focus of this perek is nikhsei melug – property that belongs to a woman who is getting married. The general rule regarding nikhsei melug, or usufruct property, is that the property remains in the woman’s possession, but her husband is okhel peirot – literally, he “eats the fruit.” In other words, she owns the property, but as long as they are married the profits accrued by the property belong to the husband.
On occasion it is difficult to distinguish between the property and the profits. Our Gemara, for example, quotes a that rules that if the woman owns beachfront property, salt and sand are considered peirot, while Rabbi Meir considers a sulfur quarry or an alum-mine to be the property itself. The Hakhamim disagree, arguing that there, too, the mined minerals are considered produce.
Rashi explains that the difference between salt/sand on the one hand and sulfur/alum on the other is that the former replenish themselves on a regular basis, while there is a limited amount of the minerals that can be mined before the reserve is used up. Thus, mining the sulfur or alum affects the property itself.
Sulfur is found in its pure form in different places throughout the world – mainly in areas with volcanic activity. The sulfur quarry described in our Gemara is a small hole dug in the ground from which the sulfur can be removed.
The alum mentioned here appears to be potash. Alum is used in the tanning process when working with hides, and is also used as a dye. Today it is used in the manufacture of paper.