Brimstone
Smith’s Bible Dictionary
Brimstone: Brimstone, or sulphur, is found in considerable quantities on the shores of the Dead Sea. (Genesis 19:24) It is a well-known simple mineral substance, crystalline, easily melted, very inflammable, and when burning emits a peculiar suffocating odor. It is found in great abundance near volcanoes. The soil around Sodom and Gomorrah abounded in sulphur and bitumen.