The rock formed by a chemical process from sedimentary origin is rock salt.

Here's why:

* Sedimentary Origin: Rock salt forms from the evaporation of water, leaving behind dissolved minerals. This process happens in shallow seas or lakes.

* Chemical Process: The primary mineral in rock salt is halite (NaCl), which is a chemical compound formed by the reaction of sodium and chlorine.

Let me know if you want to know more about the formation of rock salt!