It's a bit tricky to pin down exactly four "special" mineral properties, as there are many fascinating characteristics minerals exhibit. However, here are four properties that are often considered particularly important in defining and identifying minerals:

1. Crystal Habit: This refers to the characteristic shape or form a mineral crystal takes as it grows. Examples include cubic (like halite), hexagonal (like quartz), or platy (like mica). This is often influenced by the internal arrangement of atoms within the mineral.

2. Cleavage: This describes how a mineral breaks along specific planes of weakness due to its internal structure. Think of how mica readily splits into thin sheets, or how halite breaks into perfect cubes. Cleavage patterns are unique to different minerals.

3. Fracture: This describes how a mineral breaks when it doesn't cleave. Common fracture types include conchoidal (like glass), uneven, or splintery. Fracture can help distinguish minerals that lack perfect cleavage.

4. Streak: This refers to the color of the mineral's powder when rubbed against a streak plate (unglazed porcelain). While a mineral's external color can be misleading due to impurities, the streak color is often more consistent and helpful for identification.

Important note: While these four properties are valuable, they are not the only ones used to identify minerals. Other important properties include hardness, luster, specific gravity, and chemical composition.