MODULE 2 Flashcards
It forms naturally in the Earth’s crust without human intervention.
Naturally occurring
It is not derived from living organisms.
Inorganic
It has a definite shape and volume.
Solid
It has a uniform chemical composition throughout.
Homogenous
are naturally occurring, inorganic solids with a definite chemical composition. They are the building blocks of rocks.
Minerals
are aggregates of one or more minerals. They can be formed from different processes like volcanic eruptions, sedimentation, or metamorphism.
Rocks
What are some examples of minerals and their chemical compositions?
- Quartz: SiO2 (silicon dioxide)
- Feldspar: AT4O8 (where A can be potassium, sodium, or calcium)
- Pyrite: FeS2 (iron sulfide)
How do rocks transform from one type to another?
Rocks can transform from one type to another through the process of the rock cycle. This cycle involves three main processes:
- Igneous rocks: Formed from the cooling and solidification of magma or lava.
- Sedimentary rocks: Formed from the accumulation and cementation of sediments.
- Metamorphic rocks: Formed when existing rocks are transformed by heat and pressure.
Why are more than one property used to identify an unknown mineral?
Using multiple properties to identify a mineral is important because a single property might not be unique to a specific mineral. For example, color can be misleading as many minerals share the same color. By examining multiple properties like hardness, streak, luster, cleavage, and crystal shape, we can more accurately identify an unknown mineral.
What are the three physical properties that can be used to identify minerals?
The three physical properties that can be used to identify minerals are color, streak, and luster.
Explain the concept of “streak” as a property of minerals.
Streak refers to the color of a mineral’s powder when it is rubbed against a streak plate (unglazed porcelain). The streak color can be different from the mineral’s actual color. For example, pyrite (fool’s gold) resembles gold in color but shows a greenish black streak.
What is the significance of the image showing gold and pyrite side by side?
The image highlights the difference in streak between gold and pyrite. While both appear golden in their natural form, their streak colors differ significantly. Gold has a yellow streak, while pyrite has a greenish black streak. This visual comparison demonstrates how streak can be a useful property for distinguishing minerals.
How does “luster” relate to the way light interacts with a mineral?
Luster describes how light reflects off the surface of a mineral. It is a property that helps determine the mineral’s shine or reflectivity. For example, a mineral with a metallic luster reflects light like a metal, while a mineral with a glassy luster reflects light like glass.
Why is it important to use multiple properties to identify minerals?
Relying on only one property, like color, can be misleading because different minerals can share similar colors. Using multiple properties like color, streak, and luster increases the accuracy of mineral identification.
What are the different types of luster that a mineral can have?
Mineral luster can be either metallic or non-metallic. Non-metallic luster can be further categorized as pearly, waxy, vitreous, glassy, silky, adamantine, or sparkly, dull or clay-like, and resinous or like resins.
Explain the concept of “hardness” as a property of minerals.
Hardness refers to a mineral’s resistance to scratching. The Mohs Hardness Scale, developed by Friedrich Mohs, a German mineralogist in 1812, is a standard scale used to measure hardness. It ranks minerals from 1 (softest) to 10 (hardest), with talc being the softest and diamond the hardest.
Describe the concept of “cleavage” and how it relates to the bonding within a mineral.
Cleavage refers to a mineral’s tendency to break along specific directions at regions where the bonding is relatively weaker. The mineral can be described as having perfect, good, fair, or poor cleavage. If a mineral doesn’t break along specific planes, it is said to have fracture rather than cleavage.
What is the relationship between the spin properties of electrons and magnetism in minerals?
Magnetism in minerals arises from the spin properties of electrons that surround atomic nuclei. These spin properties are responsible for magnetic properties of a mineral. For example, magnetite, iron oxide (Fe3O4), is known for its magnetic properties.
What is fluorescence, and how does it manifest in minerals?
Fluorescence is a phenomenon where some minerals emit light when exposed to ultraviolet radiation. Minerals with fluorescence, like fluorite, stop glowing when the UV radiation source is removed.
What is the significance of the Mohs Hardness Scale?
The Mohs Hardness Scale provides a standardized method for comparing the relative hardness of minerals. It allows scientists and mineral enthusiasts to easily assess the hardness of a mineral by comparing it to known minerals on the scale.