Using known mineral samples to test the hardness of an unknown is common practice. Specific Gravity is, essentially, the minerals density when compared to the density of water. Streak is the color of a mineral in a finely powdered form. Streak properties of minerals. It is often divided into metallic and non-metallic luster.
Color is a property that describes itself.
It is the color of a mineral. Most geologist consider this property a weak differentiator among minerals. Fluorescence - becomes luminescent during exposure to UV or IR light. Phosphorescence - stays luminescent even after exposure to UV or IR light. Pyroelectricity - temperature changes will cause charges to build up on the surface.