👉 A medieval fluid, also known as a "quicksilver" or "aqua regis," was a term used in the Middle Ages to describe a highly toxic and dense liquid, often believed to be a rare form of mercury. This fluid was prized for its unique properties: it was extremely dense, nearly three times the density of water, and had a high melting point. Medieval scholars and alchemists thought it possessed mystical qualities, including the ability to pass through solid objects and its potential for creating powerful elixirs. However, due to its extreme toxicity, handling quicksilver was extremely dangerous, often leading to severe health issues or death. Its use was largely confined to alchemical experiments and mystical practices, with its true nature and properties remaining a subject of speculation and debate.