Chlorine APEX Mineral

Chlorine (Cl #17) is the next element on the periodic table for my APEX mineral collection.  

Wikipedia Chlorine
Chlorine Minerals - Most Chlorine minerals are ionic compounds (salts).

My Chlorine APEX mineral will have to be a salt even though I am trying to avoid these.  In this case, it turns out ordinary table salt (NaCl) at 61% Chlorine is by far the best choice.

Chlorine is a green gas at ambient conditions and is very reactive.  It has the highest electron affinity (releases more energy when it reacts) of any element. Sea water is 1.9% Sodium salt.  

Salt was used as early as 3000 BC and brine as early as 6000 BC

Chlorine is a critical ingredient to many industrial processes.  Chlorine compounds are often used as a disinfectant and cleaner.

Chlorine compounds are poisonous to most life forms.