Diana's Tree, Arbor Dianae, was also known as the Philosophers' Tree, Arbor Philosophorum. It is a "a dendritic amalgam of crystallized silver," named for Diana because in the alchemical world Diana stands for silver. There's a Saturn tree made of lead too! Here is a picture of the silver tree:
So, I need to investigate elsewhere to find out more about that! Wikipedia led me to this article: Alchemical Interest at the Petrine Court by Robert Collis, Esoterica, Vol VII, (2005) Online peer-reviewed journal hosted by Michigan State University. It's about Peter the Great's toleration for and interest in alchemy. He sets up the project of the article as something similar to serious investigation of Newton's alchemy.
And look what it says in here about the Tree of Diana! Marvelous (bolding is mine):
Lemery propounded a theory at odds with Geoffroy, but one that still reflected an alchemical heritage drawing on the production of a Tree of Diana, and what many at the time still believed to be the encoded alchemy of the Greco-Roman myth of Vulcan’s metallic “net”.The footnote goes into further details:
Vulcan was the Roman equivalent to the Greek craftsman-god Hephaestus. According to myth, Vulcan produced a metallic net to hang his wife, Venus, and her lover Mars, from the ceiling, after he had caught them together in bed, in order for all Olympians to see their shame. As William Newman, Professor of History at Indiana University, has described, many alchemists (including Isaac Newton) were fascinated with producing such a “net”, which George Starkey made from antimony regulus and copper. In alchemy, “Venus” refers to copper, “Mars” refers to iron and “Vulcan” is equated to fire. The antimony regulus added to the copper is reduced from a stibnite (antimony sulfide) by the addition of iron. See William Newman’s project on Newton’s Alchemy.I had linked to that project yesterday (it's the one with the special Newton Sans font for the alchemical symbols), so I expect that is where the trail will lead tomorrow.
Meanwhile, here is the story of Vulcan in 17th-century art; this sculpture is from Germany (National Gallery of Ireland):