Vegetation of Metal is a term from Alchemy which describes a metal-crystal formation, typically derived by dissolving metals in a fluid. Not unlike a modern science fair project, the minerals would eventually redeposit themselves in a somewhat tree-like branching shape. To alchemists, this was a sign of the "vital spirit", the magic spark inside the metal.
The best known Alchemical Vegetation was the Tree of Diana, which was a formation of silver, and was believed to be a step in the path to creating the Philosopher's Stone. Other variations on the experiment were known, such as the Tree of Mars which used iron instead of silver. Some Vegetations of Metal could be created in a sealed glass jar full of solvent, others required a Philosopher's Egg. This so-called "egg" was a sealed heat-resistant crucible that could be put in a furnace and heated to great temperatures.
Game and Story Use
- Little jars of branching crystalline metals would make a nice bit of scenery / set dressing for the wizard's workshop or Laboratory.
- Could be more literal (or magical) in a fantasy setting. A metallic plant, that grows, responds to the sunlight, and produces fruit or seeds. May be just a passive plant, or something more active, possibly bordering on treeman or golem.
- If your setting uses specie currency, there's probably people trying to claim it, or who realize just how bad it would be for the economy and are trying to cut it down.