Physical Properties:
* Color: This is often the first thing noticed, but can be misleading as some minerals come in a variety of colors.
* Streak: The color of the mineral's powder when rubbed against a streak plate. This is often more reliable than color.
* Hardness: Measured using Mohs Hardness Scale, which compares the mineral's resistance to scratching.
* Cleavage and Fracture: The way a mineral breaks along specific planes (cleavage) or in an irregular pattern (fracture).
* Luster: How light reflects off the mineral's surface (e.g., metallic, glassy, earthy).
* Crystal Form: The shape of the mineral's crystals, which can be a unique identifier.
* Specific Gravity: The mineral's density compared to water.
* Magnetism: Whether the mineral is attracted to a magnet.
Chemical Tests:
* Acid Test: Dropping dilute hydrochloric acid on certain minerals, like calcite, will cause them to fizz.
* Flame Test: Heating the mineral in a flame will produce a characteristic color depending on the mineral's composition.
* Chemical Analysis: More advanced techniques like X-ray diffraction, electron microprobe, and chemical analysis can be used to determine the mineral's exact chemical composition.
Other Tests:
* Optical Properties: Observing how light interacts with the mineral under a microscope.
* Fluorescence: Some minerals glow under UV light.
It's important to note that no single test is definitive, and multiple tests are often used to confirm a mineral's identity. Experience and a combination of tests are crucial for accurate identification.
