This symbol is popularly referred to as a Leviathan Cross, named after Anton Lavey, who dabbled in the occult and adopted it as an emblem of Satanism in the 60s. A satanic cross is a curious notion because unlike Jesus, Satan was never crucified; rather he rejected the Grace of God.
Satanists may curse us if they wish, but since there is no monopoly on cross shapes, on this page we are reclaiming any satanic association of the symbol for its Christian interpretation.
also called a Leviathan Cross
Brimstone is the lemon coloured stone found at the brim of volcanoes and hot springs. This chemical is now more usually known by its Latin name sulfur, and the term 'brimstone' tends to be reserved for references in ancient texts such as the Bible.
More common symbol for sulfur
Alchemists have used different symbols for sulfur, including the upward-pointing triangle surmounting a cross. The triangle in alchemy symbolises fire, and the cross symbolises earth.
There is an interesting similarity with Chinese and Japanese characters where 'fire' is shown as and 'earth' is represented as . Similarly with the double-barred cross of the brimstone symbol, the Sino-Japanese character for 'out' is , which may be an old pictogram for an erupting volcano.
Sulphur happens to be an element that is essential for life and it is no coincidence that the same symbols are used in Christianity. The triangle and the cross symbolise the divinity of Christ and salvation. The cross represents life and when this is combined with the infinity symbol the meaning is everlasting life.
Traditionally spelt 'sulphur' in British English, but universally as 'sulfur' in chemistry.
The character symbolises a small mountain on top of a larger mountain, representing the subaerial growth due to volcanic activity.
See also Pagan Symbols used in Christianity