The Philosopher's Stone

The Philosopher's Stone is a material that is only found on planets that developed sentient life, usually in a single gemstone somewhere on the planet's surface. The origin of the material, and of the stones as well, is unknown, as is the relation between them and life on the planet. If it is life that causes the stone or the stone that causes life is up for debate. What is known, however, is that the Philosopher's Stone is able to amplify alchemical powers to extreme levels, to the point where the basic law of alchemy - that matter and energy can be neither created nor destroyed - can be ignored. It is the discovery of the stone that propels most space-faring species into their interstellar era, due to its ability to create energy and matter.

Properties of the Philosopher's Stone
The Philosopher's Stone is made from a material that is not found anywhere else in nature, or the galaxy. It is only found on planets with sentient life, and on all scans of it for non-visible light radiation, it seems to not exist. It lacks mass and chemically reacts with nothing, not even Alkahest (the universal solvent).

The mechanism responsible for it amplifying alchemical reactions is unknown, but it presumably has something to do with its lack of mass or radiation beyond visible light.

The usage of it is responsible for nearly all space-faring civilization's formation and only very few species developed space travel prior to their discovery of it.

Usage of the Philosopher's Stone in war is highly dangerous,as it allows for someone using it to effectively create entire armies from nothing or to destroy entire planets. Only the usage of another Philosopher's Stone countering another stone can stop its effects.

Legal Status
The various factions across the galaxy have all signed treaties forbidding the usage of Philosopher's Stones in any way, peaceful or otherwise. The initial treaties signed between the Early Space-Faring Races (the Philosopher's Union) had the stones in possession of all participants shattered and scattered across the galaxy, which was only able to be done by using other stones. The single non-shattered stone has been stored in an undisclosed system of the galaxy, to prevent anyone from retrieving it.

The Philosopher's Union has enforced this policy of scattering parts of the Philosopher's Stones across the galaxy to prevent anyone from using them again rigorously, fearing any nation getting a working stone. Any individual or entity (legal or otherwise) that comes into possession of the stone and refuses to comply to this policy is labeled an enemy to galactic civilization, and is legally allowed to be hunted down to prevent the balance of power from being disturbed.

Squads are being sent to all planets developing life to prevent them from ever finding their Philosopher's Stone, and to figure out if sentient life causes it or if it causes sentient life. While various factions have deemed this a violation of Living Rights, it has been upheld by the Philosopher's Union and all other legally enabled organizations.