Did you know that in ancient alchemy, seven metals were the basis for all experiment? These included:

  • Gold
  • Silver
  • Copper
  • Mercury
  • Lead
  • Tin
  • Iron

And furthermore, the practice of alchemy was devoted to uncovering universal secrets. Therefore each of those seven earthly metals was associated with a heavenly body:

GoldSun
SilverMoon
MercuryMercury
CopperVenus
IronMars
LeadSaturn
TinJupiter

This idea of linking metals to planets also led alchemists to study astrology, emphasizing certain days of the week or phases of the moon for their experiments. And though it seems antiquated now, then it was considered simple fact, which inspired alchemists for centuries.

References, including title quote, taken from: Thompson, C.J.S. Alchemy and Alchemists, Dover edition: 2002, p 16.