Why do halite crystals always break into smaller crystals and the same shape?

Because Because of the 3D pattern of alternating positive and negative ions

Explanation:

Halite’s crystals is formed from evaporation of seawater and brine lakes. It can also be found in those ancient lakes or restricted seas that were cut off, and later evaporated. Because it s found in evaporated seas, halite can as well be found with other minerals like Sylvia, calcite, anhydrite.

Halite forms clear transparent crystals that exhibit perfect cubic cleavage.It

can be distinguish from other crystals because of its distinctive properties, one of these properties is it's salty taste.

When halite is broken into small pieces, it will readily dissolve in water.

The test for Halite is by filling one's finger with moisture, then rub the moisturized finger with the sample then taste the rubbed finger.Halite is softer compare to glass.

Therefore, the reason why halite crystals always break into smaller crystals and the same shape is Because of the 3D pattern of alternating positive and negative ions.