Greenish. That is the meaning of the Greek word khlorós, which gave its name to the natural chemical element with the symbol CI 17, one of the 100 that make up the structure of our planet. Despite being the 21st most abundant chemical element in the Earth's crust, chlorine is rare in its free form and is found in nature combined with other elements, mainly as sodium chloride. Yes, you read that correctly - its most common compound is simple table salt, known since ancient times, with archaeological evidence that it has been used for more than eight thousand years.
Chlorine itself, and its fundamental properties for human civilisation, was only discovered much more recently. It was officially discovered in 1774, although, in 1630, chlorine gas had already been synthesised for the first time in a chemical reaction in the alchemist experiments of the Belgian chemist Jan Baptist van Helmont, who did not realise its importance.