I think Calcite. Calcite is 3 on the hardness scale and sometimes you can break it into cubes. The difference between Calcite and Quartz is that Calcite is a milky white.
cleavage....
Diamond has perfect cleavage in four directions, fluorite has perfect cleavage in four directions, sodalite has perfect cleavage in three directions, and sphalerite has perfect cleavage in six directions.
Calcite exhibits cleavage in three directions.
Cleavage in minerals can be identified by observing how the mineral breaks along certain planes or directions, resulting in smooth, flat surfaces. This cleavage is a result of the internal atomic structure of the mineral. By examining the shape and pattern of the breakage, one can determine the cleavage of a mineral.
Cleavage is the property that examines a mineral's ability to break into even pieces along specific planes or directions. Minerals with good cleavage will break cleanly and smoothly along these planes, while minerals with poor cleavage will break in irregular or jagged shapes. Cleavage is determined by the internal atomic structure of a mineral.
cleavage....
The ability of a mineral to break along preferred directions is called cleavage. Cleavage is a result of the arrangement of atoms within the mineral structure, which causes it to break in certain directions more easily than others.
Diamond has perfect cleavage in four directions, fluorite has perfect cleavage in four directions, sodalite has perfect cleavage in three directions, and sphalerite has perfect cleavage in six directions.
...directions of cleavage...
The term used to describe the shape of a mineral with three directions of cleavage that intersect at 90 degrees is cubic or isometric cleavage. This means that the mineral can cleave in three directions at right angles to each other, resulting in cubic-shaped fragments.
Calcite exhibits cleavage in three directions.
cube
Cleavage in minerals can be identified by observing how the mineral breaks along certain planes or directions, resulting in smooth, flat surfaces. This cleavage is a result of the internal atomic structure of the mineral. By examining the shape and pattern of the breakage, one can determine the cleavage of a mineral.
Two directions of cleavage, at 90 degrees to each other.
Rock salt.
minerals with cleavage break along smooth, flat surfaces in one or more directions.
Cleavage is the property that examines a mineral's ability to break into even pieces along specific planes or directions. Minerals with good cleavage will break cleanly and smoothly along these planes, while minerals with poor cleavage will break in irregular or jagged shapes. Cleavage is determined by the internal atomic structure of a mineral.