The term Brimstone is synonymous to pure sulfur balls containing 96-98% sulfur with traces of magnesium that burn at 4,000 - 6,000 degrees Fahrenheit. Meteorites contain sulfur and all excavations of the 5 Plain Cities contain golf sized balls of pure sulfur that burn through rock and virtually all matter. The sulfur balls when tested today burn a blue flame, tastes and smells like sulfur. None of the structures stood a chance against the pure sulfur balls we commonly call brimstone.
The Five Plain Cities also known as the cities of the plain were Admah, Zevoiim, Sodom, Gomorrah and Zoar. The following scriptures reference all five cities once located in the Dead Sea Area.
Genesis 14:1-24 And it came about in the days of Amraphel king of Shinar, Arioch king of Ellasar, Chedorlaomer king of Elam, and Tidal king of Goiim, that they made war with Bera king of Sodom, and with Birsha king of Gomorrah, Shinab king of Admah, and Shemeber king of Zeboiim, and the king of Bela (that is, Zoar). All these came as allies to the valley of Siddim (that is, the Salt Sea).
Deuteronomy 29:23 'All its land is brimstone and salt, a burning waste, unsown and unproductive, and no grass grows in it, like the overthrow of Sodom and Gomorrah, Admah and Zeboiim, which the LORD overthrew in His anger and in His wrath.'