In 1811, a chemist added too much acid to seaweed ash, and purple vapor revealed iodine

In the heart of 1811, a serendipitous moment unfolded in the laboratory of French chemist Bernard Courtois. As he endeavored to create saltpeter from seaweed ash, his overzealous addition of sulfuric acid resulted in an ethereal violet vapor. This vibrant apparition heralded the discovery of iodine, a moment that would echo through the realms of chemistry, medicine, and public health.

Raccontata daeconomictimes.indiatimes.com