The repeating patterns are the latticework of the crystalline structure.
An atom is the smallest bit of matter that isn't a sub-atomic particle. Minerals are made of atoms.
Some minerals with closely packed atom structure have a high density.
Crystals.
Atom
The mineral you are referring to is sulfate. Sulfate minerals contain a sulfate ion, which consists of a sulfur atom bonded to four oxygen atoms. Examples of sulfate minerals include gypsum (CaSO4·2H2O) and barite (BaSO4).
Striations in minerals are fine, parallel lines or grooves that occur on the surface of a mineral crystal. These features often indicate the growth patterns of the crystal as it formed, reflecting variations in conditions such as temperature and pressure. Striations can also be used to help identify specific minerals, as different minerals exhibit unique striation patterns. They are commonly observed in minerals like feldspar and quartz.
Crystals.
All atoms are a fuzzy, indistinct shape.
Some minerals with a closely packed atom structure have a high density. This close packing of atoms results in a tightly packed crystal lattice, leading to a high atomic mass per unit volume. Examples of such minerals include diamond and gold.
Probably buy telling which mineral is denser
The visible shape of a mineral's pattern is called a crystal. Solidified minerals that are from a molten state have smooth faced, angular crystals.
A mineral is a non-organic substance made of a single type of atom; as opposed to a compound or a rock. So a mineral is something like a diamond which is only made of the carbon atom, whereas a rock is something like limestone which is made of multiple minerals.