It's not accurate to say there are only two physical properties of minerals. Minerals are defined by their chemical composition and crystal structure. These properties lead to a wide range of observable physical properties, which are used to identify and classify minerals.

Here are some of the most common physical properties used to identify minerals:

* Color: The visual appearance of the mineral in reflected light.

* Streak: The color of the mineral's powder, which can be different from the mineral's color.

* Luster: The way light reflects off the mineral's surface, described as metallic, glassy, pearly, etc.

* Hardness: The mineral's resistance to scratching, measured on the Mohs Hardness Scale.

* Cleavage: The tendency of a mineral to break along specific planes of weakness, creating smooth, flat surfaces.

* Fracture: The way a mineral breaks when it doesn't cleave, described as conchoidal, splintery, etc.

* Crystal Habit: The typical shape or form in which a mineral crystallizes.

* Specific Gravity: The ratio of the mineral's density to the density of water.

* Magnetism: Whether the mineral is attracted to a magnet.

* Fluorescence: Whether the mineral emits visible light when exposed to ultraviolet light.

So, while there are countless physical properties that minerals exhibit, these are some of the most important and frequently used in mineral identification.