mineral properties.

• Lustre is the way a mineral reflects light and is controlled by atomic structures. It can be pearly, dull, metallic, or silky.
• Streak is the color of powder produced when a mineral is scratched on a porcelain tile, useful for identifying metallic minerals.
• Hardness is measured on Moh's scale from 1-10.
• Acid reaction tests for carbonates, with dilute HCL causing effervescence for a positive result.
• Colour is determined by chemical composition and is not very useful for identification.
• Cleavage is the way a mineral breaks under a hammer, determined by lines of weakness in the atomic structure. It can be perfect, good, or poor.
• Fracture is the way a mineral breaks under a hammer and is not controlled by atomic structure. It can be conchoidal, even, or uneven.
• Magnetic properties are exhibited by magnetite, the only strongly magnetic material on Earth's surface.
• Form/habit refers to the 3D natural shape of a mineral, which can be acicular, tabular, or bladed.