"Of the material sold during the 1936 Sotheby's auction, several documents indicate an interest by Newton in the procurement or development of The Philosopher's Stone. Most notably are documents entitled, "Artephius his secret Book", ... "The Epistle of Iohn Pontanus"..... , these are themselves a collection of excerpts from another work entitled, "Nicholas Flammel, His Exposition of the Hieroglyphicall Figures which he caused to be painted upon an Arch in St Innocents Church-yard in Paris. Together with The secret Booke of Artephius, And the Epistle of Iohn Pontanus: Containing both the Theoricke and the Practicke of the Philosophers Stone". ... Nicolas Flamel, (one subject of the aforementioned work) was a notable, though mysterious figure, often associated with the discovery of The Philosopher's Stone, Hieroglyphical Figures, early forms of tarot, and occultism. Artephius, and his "secret book", were also subjects of interest to 17th century alchemists."
As told in the previous post, Isaac Newton became the Master of the Mint. In the case that he had actually discovered the Philosopher's Stone.