The mineral that precipitates from oceans and rock salt is halite, which is the mineral form of sodium chloride (NaCl).

Here's why:

* Ocean Water: Ocean water is a salty solution containing dissolved minerals, with sodium chloride being the most abundant. As water evaporates, the concentration of dissolved salts increases, leading to the precipitation of halite. This is how salt flats form.

* Rock Salt: Rock salt is formed from ancient evaporated seas. Over millions of years, the evaporated sea water left behind thick layers of halite, which eventually solidified into rock salt deposits.

So, the mineral that precipitates from oceans and rock salt is halite (NaCl).