Sulfur
Also called sulphur, the combustible principle
Paracelsus, sixteenth century, for the principle; the stone is ancient
Alchemy symbolsSulfur meaning
In alchemy, sulfur is the combustible principle: what burns and what gives a substance its character. It is one of the three principles with mercury and salt, not the element on a modern periodic table.
What burns, and what gives a thing its character.
The name. The alchemical sulfur is not only the yellow element. A triangle over a cross is the usual sign.
Where it comes from
Paracelsus’s tria prima are sulfur, mercury, and salt — principles you can watch in a fire. Something burns, something fumes, something stays. He promoted the observation into a theory of metals and of persons. The glyph here is the triangle of fire set on a cross. A different sign, a cross under a lemniscate, is the “leviathan” sulfur of later occultism. Do not swap them silently.
Alchemy
Soul, in the language of the furnace
Sulfur is the hot principle: form that acts, the reason a substance behaves like itself when you stress it. In the human analogy it is closer to character than to mood. It binds. It also consumes. A working alchemist and a spiritual reader can use the same word and not be having the same day in the lab.
Alchemy
The three stay three
Mercury mediates and flies. Salt remains. Sulfur specifies. None of them replaces the four elements, which operate at another level of the old physics. If a text mixes the systems without saying so, it is probably modern.
Near this
Sources
- Paracelsian tria prima: sulfur, mercury, salt
Named when the entry depends on a text, a date, or a standard. Catalog numbers are not invented.
Your margin
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symbol.wiki, edited as Sigilla. Last reviewed 2 October 2026. A reading of public tradition, not a ruling.