Unit 2 – Rocks And Minerals Notes

Unit 2 – Rocks and Minerals Notes

Minerals are naturally occurring, inorganic, solids, with a crystalline structure, and definite composition, that cannot be broken into smaller substances.

Rocks are a mixture of minerals.

Physical properties can be observed or measured without changing the composition of matter.

Physical properties are used to observe and describe matter.

Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, and many others.

True color of the mineral samples is occasionally hidden by tarnish, rust, corrosion, or even soil. Some minerals might be found in a wide variety of colors.

Luster is the way light reflects from a mineral. Luster can be described as metallic, glassy, pearly, dull, and sparkling.

The resistance of a mineral to being scratched is known as hardness. Mohs Hardness Scale uses common objects (fingernail, penny, nail, glass) of a known hardness to scratch the minerals and rank its hardness from 1 to 10. 1 is the softest (talc) 10 is the hardest (diamond).

Streak is one of the most reliable properties used in identifying minerals. Streak refers to the color of the powder a mineral leaves after rubbing it on an unglazed porcelain streak plate. Note that this is not always the same color as the original mineral.

Specific gravity is the comparison of the mineral’s density to the density of water (1g/mL). Rock Cycle Vocabulary  Deposition – the natural process of adding transported sediments to a landform.  Erosion – the transport of fragments of rock by water, wind, ice, or gravity.  Extrusive igneous rock – rock formed from the cooling of molten rock on Earth’s surface.  Intrusive igneous rock – rock formed from the cooling of molten rock below Earth’s surface.  Lava – molten rock that has erupted onto Earth’s surface.  Lithification – the compaction and cementing of sediment into rock.  Magma – molten rock below Earth’s surface.  Metamorphic rock – rock that has been changed by heat and pressure.  Rock cycle – a continuous series of events through which a rock is transformed from one type to another.  Sediment – rock fragments that have been transported to a different location.  Sedimentary rock – rock formed from sediments, organic remains, or chemical precipitates.  Soil – the top layer of Earth’s surface that supports plant growth.  Weathering – the breakdown of rock due to rain, wind, ice, sunlight, and plants.