The Heaven of the Philosophers, or the Book of Vexations

and a nobler, non-friable but malleable body is rendered.

45. The alchemist then approaches, who corrupts, mortifies, and artificially prepares such a metallic body again: thus, in the same way, that metallic Spiritus spirit/essence assumes a nobler and more perfect body, manifesting itself into the light, either into the Sun or the Moon: and thus the metallic spirit and body, perfectly united together, are safe from the corruption of elemental fire, and indeed are incorruptible.

Canon 7

46. The seventh of the six spiritual metals is the corporeal Sun, which in itself is nothing other than pure fire. As for what it is externally, it possesses a body that appears beautifully in flames and is more perfect, heavier, colder, and more homogeneous to sight and touch. The reason for this is that it contains within itself the coagulations of the other six metals, by which it has been made most compact in one external body.
47. Its liquefaction through elemental fire proceeds or is caused by the liquefactions of mercury, lead, and water original: "viscum" likely refers to lead or a metallic sludge; "aquarum" refers to metallic liquids, which are spiritually hidden within it. A most manifest example of this is that Mercury more easily mixes corporally with the Sun through an embrace.
48. But the Sun, after liquefaction, when heat recedes and cold...