The Brenstone Mine is a child Biome of the Swamp.
A Brenstone Mine features a large circle of Clay in the Swamp, often with exposed blocks of Sulfur. Brenstone mines can take the form of either a small hill or depression. Beneath the sulfur deposits, plentiful amounts of Quartz can usually be found.
Being inside the Swamp means that survivors will need to keep an eye out for mainly Raptors and Sarcos. The swamp's numerous carnivorous plants can also pose a problem.
A cross section of a Brenstone Mine, showing its layered resources.
Many survivors have noted they sometimes find Spinel Ore deposits mixed with the Quartz under brenstone mines.