That is definitely an alchemist sign. What precisely it means is lost to the ages. Many used their own language code, so it could mean anything.
When I learned about Universal symbols in shrink school we were taught that if they come from a dream or spontaneous writing, you have considerable leeway in determining meaning.
If you bisect the image horizontally, it is a very old ideogram for fire. So the actual image and the image itself reversed would be double fire? It was also used to signify a halo around the Moon. Double moon halo? That double image could also represent the golden number 18. It was used to calculate the phases of the moon in medieval times.
This could be a combination of symbols to represent a formula. The straight vertical line signifies one single element. The fire symbol and the upside-down fire symbol could mean this was an element heated twice to change its properties.
Does any of this resonate with you?