Mdl Flashcards
What are rocks defined as?
An aggregate of minerals and silicates predominantly found in the solid state of matter.
How are rocks categorized?
Rocks are split into separate categories that define the way they were formed.
What are minerals?
Naturally occurring substances made from geological processes.
What are the characteristics of minerals?
- A mineral is a naturally occurring substance.
- A mineral is inorganic.
- A mineral is a homogenous solid.
- A mineral has a definite chemical composition.
For example, feldspars are aluminosilicate minerals with the general formula AT408.
What is the definition of polymorphic minerals?
Minerals that share common chemical composition but with different crystalline structure.
What are examples of polymorphic minerals?
Graphite and diamond.
What does it mean for a mineral to have a crystalline structure?
The atoms in a mineral are arranged in a systematic and repeating pattern.
How is the crystallinity of minerals determined?
Using X-ray diffraction (XRD) techniques.
What are mineraloids?
Mineraloids have the characteristics of a mineral but without ordered internal structure.
What are examples of mineraloids?
Opal, volcanic glass (obsidian), and polished quartz.
How many different minerals are there approximately?
Approximately 4000 different minerals.
What are physical properties used to identify minerals?
Color, Streak, and Luster.
What is color in terms of identifying minerals?
The perceived wavelength of light that bounced off from the material and is detected by our eyes.
What is streak in terms of identifying minerals?
The color of a crushed mineral’s powder.
What is luster in terms of identifying minerals?
The behavior of light as it is reflected by the mineral.
What is luster?
Luster is the surface appearance of a mineral. It can be metallic (pearly, waxy, vitreous or glassy, silky, adamantine or sparkly, dull or clay-like, and resinous or like resins)
What is hardness?
Hardness is the resistance of a mineral to scratching. Friedrich Mohs developed the scale in 1812.
What is the Mohs Hardness Scale?
The Mohs Hardness Scale is a scale developed by Friedrich Mohs to measure the hardness of minerals.
What is cleavage?
Cleavage is the tendency of a mineral to break along particular directions at regions where the bonding is relatively weaker. It can be described as perfect, good, fair, or poor.
What is fracture?
Fracture is when a mineral doesn’t have a planar cleavage.
What is magnetism?
Magnetism is the tendency of a mineral such as magnetite, iron oxide (Fe3O4) to be attracted to a magnet.
What is fluorescence?
Minerals with fluorescence like fluorite stop glowing.
What is phosphorescence?
Minerals with phosphorescence can glow for a brief time after the light source is turned off.
Example minerals: calcite, celestite, colemanite, fluorite, sphalerite, and willemite
What does effervescence describe?
Effervescence describes the reactivity of minerals to dilute hydrochloric acid (HCI).
Example minerals: calcite and dolomite
