1. Color: While not always reliable (some minerals have many color variations), color can be a helpful starting point. For example, a bright blue mineral is likely Azurite.
2. Streak: This refers to the color of the mineral's powder when rubbed against a streak plate (unglazed porcelain). Streak can be more consistent than color, as it isn't affected by surface variations.
3. Hardness: The Mohs Hardness Scale measures a mineral's resistance to scratching. A simple test involves seeing if a mineral can scratch glass (hardness 5.5) or be scratched by a fingernail (hardness 2.5).
4. Cleavage and Fracture: How a mineral breaks can be very informative. Cleavage refers to a smooth, flat break along a specific plane. Fracture refers to an uneven, irregular break.
5. Luster: This describes how light reflects off a mineral's surface. Common lusters include metallic, glassy, pearly, and earthy.
6. Crystal Form: Minerals often form with distinct geometric shapes. This can be a useful identification tool, though many minerals are found in irregular forms.
7. Specific Gravity: This is the ratio of a mineral's density to the density of water. It can be determined by weighing the mineral in air and then in water.
Important Note: For reliable mineral identification, it's often necessary to use a combination of these methods. Additionally, consulting field guides or a knowledgeable geologist can greatly assist with accurate identification.