1. Hardness: This refers to a mineral's resistance to scratching. The Mohs Hardness Scale is used to compare the relative hardness of minerals. Diamond is the hardest known natural mineral.

2. Cleavage: This is the tendency of a mineral to break along smooth, flat surfaces. The direction and quality of cleavage can be used to identify different minerals.

3. Luster: This describes how light reflects off the surface of a mineral. Luster can be metallic, glassy, pearly, or dull, among others.

4. Color: While color can be a helpful indicator, it's not always a reliable way to identify minerals. Many minerals come in a variety of colors due to impurities.

Let me know if you'd like more details on any of these properties or would like to explore other physical properties!