kinda like the question "why is the fire orange?" sciencist can answer "because of the sodium", but that still does not answer why, because of the sodium, is the fire orange. And to search for meaning behind it, people can sometimes make up "reasons" to answer why: "Because Zeus made fire orange, duh", and then a mythology is born.
The point is not dive too into the details, is Gandr some sort of containment field that captures gravity or kinetic force to destroy an object? What particle is associated with magical energy? The magus answer is "best if we do not know all the details" because once you understand every nook and cranny around around certain system or tool, you'll start to see imperfections and weaknesses. In other words keeping the detail mysterious, while it still works, make it stronger.