Chlorine, iodine, bromine, and fluorine are all halogens, meaning they belong to the same group on the periodic table. They are highly reactive and readily form salts with metals.

However, they don't typically combine directly with each other to form minerals.

Here's why:

* Ionic Bonding: Halogens are highly electronegative, meaning they tend to gain electrons. When they react with metals, they form ionic bonds, where the metal loses electrons and the halogen gains them.

* Similar Reactivity: Since they all have similar reactivity, they are more likely to react with other elements rather than with each other.

Examples of minerals formed by halogens:

* Halite (NaCl): Common table salt, formed by the reaction of sodium and chlorine.

* Sylvite (KCl): Potassium chloride, used as a fertilizer.

* Fluorite (CaF2): Calcium fluoride, used in steelmaking and as a flux.

Note: While halogens can sometimes form interhalogen compounds (like BrF3 or ClF5), these are generally not found as naturally occurring minerals.