Halite (next page) breaks into cubes (three cleavages at right angles) and tastes like table salt.
These five halite crystal fragments show halite's cubic cleavage (three cleavages at right angles). Note that minerals do not always break into perfect 6-sided cubes or even rectangles. Cleavage planes are zones of weakness, not destiny.
The white blobs are spots of paint on the bottom of the fragments.
Rock salt comes in a variety of dirty colors, depending on impurities. If you broke these up, you might get some good cleavage planes. The planes intersection would make little corners like those of a box (outside corner) or a room (inside corner).
The larger block of rock salt shows some reflections from either cleavage planes or crystal faces that suggest the cubic nature of halite crystals.
Blocks of halite found in the wild (normally only in deserts, for halite is very soluble) tend to look partially dissolved. This sample is from the Mojave Desert of California.