1. Crystal Form:
* Habit: Refers to the overall shape of a mineral crystal. Examples include cubic, hexagonal, prismatic, platy, and dendritic.
* Cleavage: The tendency of a mineral to break along specific planes of weakness. Described by the number of cleavage planes and their angles.
* Fracture: How a mineral breaks when it doesn't follow a cleavage plane. Examples include conchoidal (curved, shell-like), uneven, and splintery.
2. Color:
* Streak: The color of a mineral's powder, obtained by rubbing it against a streak plate.
* Luster: The way light reflects off the surface of a mineral. Examples include metallic, vitreous (glassy), pearly, silky, and dull.
3. Hardness:
* Mohs Hardness Scale: A relative scale that measures a mineral's resistance to scratching. Minerals are compared to known minerals on the scale, from talc (softest, 1) to diamond (hardest, 10).
4. Specific Gravity:
* Density: The ratio of a mineral's mass to its volume. This can be determined by comparing the weight of the mineral to the weight of an equal volume of water.
5. Other Properties:
* Magnetism: Some minerals are attracted to a magnet.
* Taste: Some minerals have a distinct taste (halite – salty, sylvite – bitter).
* Smell: Some minerals have a distinctive odor, especially when rubbed or scratched.
* Fluorescence: Some minerals emit visible light when exposed to ultraviolet light.
* Radioactivity: Some minerals are radioactive.
Using Physical Properties for Identification:
1. Observe and record: Carefully observe the mineral's physical properties and note them down.
2. Compare: Use a mineral identification guide, field book, or online resource to compare your observations to the properties of known minerals.
3. Consider: Keep in mind that some minerals can have similar properties, so you may need to combine several characteristics for accurate identification.
Important Note:
* While physical properties are a helpful tool for mineral identification, it's crucial to use multiple properties for a more accurate identification.
* Always handle minerals responsibly and avoid ingesting or inhaling them.
