An alchemical symbol is like a secret code that alchemists (people who wanted to turn stuff into gold) used to describe different substances and their properties. It's like how you use symbols to tell a story in your drawings, but alchemists used symbols to tell a story about chemicals and how to turn them into something else.
For example, the symbol for gold is a circle with a dot in the middle, which represents the sun. The symbol for mercury is a crescent moon, which represents its liquid state and ability to change. The symbol for sulfur is an equilateral triangle, which represents its stable and enduring properties.
Alchemists would use these symbols to communicate with other alchemists about their experiments and findings. They could write down their secrets without worrying that someone who wasn't an alchemist would understand what they were talking about.
Even though alchemy is not a popular practice anymore, many of these symbols are still used in chemistry today! Scientists use them to represent different elements and compounds. So, even though they may seem like a secret code, alchemical symbols are actually little keys to unlock the mysteries of chemistry!