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.
How can the properties discussed in the image be used to identify minerals?
By examining a mineral’s luster, hardness, cleavage, magnetism, and fluorescence, one can gain insights into its composition and structure. These properties, when combined, can help differentiate between various minerals and aid in their identification.
crystallize below Earth’s surface, and the slow cooling that occurs there allows large crystals to form. Examples include diorite, gabbro, granite, pegmatite, and peridotite.
- Intrusive rocks (Plutonic Rocks)
erupt onto the surface, where they cool quickly to form small crystals. Examples include andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria, and tuff.
- Extrusive rocks (Volcanic Rocks)
What is the main difference between rocks and minerals?
Rocks are defined as an aggregate of minerals and silicates, while minerals are naturally occurring substances made from geological processes that possess specific characteristics.
The perceived wavelength of light that bounces off the mineral and is detected by our eyes.
Color
The color of a mineral’s powder when rubbed against a streak plate.
Streak
How the mineral reflects light, described as metallic, glassy, or dull.
Luster
The resistance of a mineral to scratching, measured on Mohs Hardness Scale.
Hardness
What is meant by the term “crystalline structure” in relation to minerals?
Crystalline structure refers to the ordered internal arrangement of atoms within a mineral. This arrangement creates a systematic and repeating pattern, which is not visible to the naked eye but can be determined using X-ray diffraction techniques.
Formed from the cooling and solidification of molten rock (magma or lava).
Igneous rocks
Formed from the accumulation and cementation of sediments, like sand, gravel, or shells.
Sedimentary rocks
Formed when existing rocks are transformed by heat, pressure, or chemical reactions.
Metamorphic rocks
What is the significance of the chemical composition of a mineral?
The chemical composition of a mineral determines its physical and chemical properties. For example, quartz (SiO2) is a hard and resistant mineral due to its strong silicon-oxygen bonds.
How can the properties of minerals be used to identify them?
By observing and testing the properties of a mineral, such as color, streak, luster, hardness, and crystal structure, scientists can identify and classify them. This knowledge helps in understanding the formation, composition, and uses of minerals.
It refers to the formation of
rock crystals in cooling magma.
CRYSTALLIZATION
desublimation, or gas to solid
phase transformation
DEPOSITION
alters a
rock’s chemical composition
driven basically by temperature
and pressure.
Chemical Weathering
Allows the breakdown of rocks into
smaller pieces.
Physical Weathering
It is the geological process in
which earthen materials are
worn away and transported by
natural forces such as wind or
water.
EROSION
It is the movement of
sediments from one place to
another
TRANSPORT
It is the setting of the sediments in an area before
they are finally lithified to form
sedimentary rocks.
Deposition in sedimentary rocks
It is the group of processes
responsible for the
transformation of sediments
(sand)
into sedimentary
rocks (sandstone).
DIAGNESIS OR LITHIFICATION
(compaction and cementation)
is formed when minerals, dissolved in
water, begin to precipitate out of
solution and deposit at the base of the
water body such as oolitic limestone,
halite (rock salt), sylvite, baryte and
gypsum.
Chemical
is a sedimentary rock,
composed mainly of calcium carbonate or
dolomite, used as building material and in
the making of cement.
Limestone
An inorganic solid material found in nature is a(n) ________.
Crystal
- Explanation: A crystal is a naturally occurring solid with a specific, repeating internal arrangement of atoms. Minerals are naturally occurring inorganic solids with a definite chemical composition and a specific crystal structure.
A(n) _______ is usually made of two or more minerals.
Rock
- Explanation: Rocks are naturally occurring solid materials composed of one or more minerals.
What is the difference between cleavage and fracture?
Cleavage produces pieces with smooth, regular edges.
Fracture produces pieces with rough edges.
is the tendency of a mineral to break along specific planes of weakness, resulting in smooth, flat surfaces.
Cleavage
occurs when a mineral breaks irregularly, producing uneven or jagged surfaces.
Fracture
Cleavage is caused by ______.
weaknesses in the arrangement of the atoms
What does the streak test for minerals help do?
identify minerals
The Mohs scale classifies minerals by their ______.
hardness
