Understanding Minerals and Rocks: Key Concepts and Definitions
Understanding Minerals and Rocks: Key Concepts and Definitions
1. What is the Definition of a Mineral?
– A mineral is a naturally occurring, inorganic solid with a definite chemical composition and a crystalline structure.
2. How Does a Rock Differ from a Mineral?
– Rocks are aggregates of minerals or organic material, whereas minerals are individual, naturally occurring substances with specific chemical compositions.
3. What Are Common Crystal Shapes?
– Common crystal shapes include cubic, hexagonal, tetragonal, orthorhombic, monoclinic, and triclinic.
4. What is Cleavage? How Does it Differ from Fracture?
– Cleavage is the tendency of a mineral to break along planes of weakness, producing smooth surfaces. Fracture, on the other hand, is the way a mineral breaks when it doesn’t cleave, resulting in irregular surfaces.
5. What is the Color of a Mineral? Is it the Best Way to Identify All Minerals?
– The color of a mineral can vary, but it is not always a reliable indicator of mineral identity due to impurities. Other properties like streak, hardness, and specific gravity are often more reliable for identification.
6. What Are Different Lusters?
– Luster refers to the way light interacts with the surface of a mineral. Common types include metallic, vitreous (glassy), pearly, greasy, and dull.
7. What is Hardness and How Do We Determine It?
– Hardness is a measure of a mineral’s resistance to scratching. It is determined using the Mohs scale of hardness, which ranks minerals from 1 (softest) to 10 (hardest).
8. What Are the 10 Minerals on the Mohs Hardness Scale?
– The minerals on the Mohs hardness scale, from softest to hardest, are:
- Talc
- Gypsum
- Calcite
- Fluorite
- Apatite
- Orthoclase Feldspar
- Quartz
- Topaz
- Corundum
- Diamond
9. What Does it Mean if the Mineral Effervesces (Fizzes)?
– Effervescence occurs when a mineral reacts with acid, usually indicating the presence of carbonate minerals like calcite.
10. What is Density? What Elements Can Make Minerals Dense?
– Density is the mass of a substance per unit volume. Elements like iron, lead, and gold can contribute to the density of minerals.
11. What is Magnetism and How Can it Be Used to Identify a Mineral?
– Magnetism is the property of being attracted to a magnet. Some minerals, like magnetite, exhibit natural magnetism, which can be used for identification.
12. How Does the Internal Atomic Arrangement Affect Crystal Shape?
– The internal atomic arrangement determines the geometric arrangement of atoms within a crystal lattice, influencing its overall shape.
13. How Can the Environment in Which a Crystal Forms Affect its Shape?
– Environmental factors such as temperature, pressure, and available space can influence crystal growth, affecting the final shape of a crystal.
14. What Types of Bonds Cause a Mineral to Cleave?
– Cleavage is often caused by the presence of weak atomic bonds, such as those found in ionic or covalent bonds.
15. List the Common Types of Cleavage, the Shape They Form, and a Mineral Example.
– Cubic cleavage (forms cubes): Halite (salt)
– Rhomboidal cleavage (forms rhomboids): Calcite
– Sheet cleavage (forms sheets): Muscovite (mica), Biotite (mica)
16. What Common Minerals Have Sheet Cleavage, Cubic Cleavage, and Rhomboidal Cleavage?
– Sheet cleavage: Muscovite and Biotite
– Cubic cleavage: Halite
– Rhomboidal cleavage: Calcite
17. Students Should Be Able to List and Describe the Different Classes of Rock-Forming Minerals Based on Their Chemistry, as Well as Common Examples of Each.
– Silicates: Silicates are minerals containing silicon and oxygen, bonded with various metals. Common examples include quartz, feldspar, and mica.
– Carbonates: Carbonates are minerals containing carbonate ions (CO3^2-) bonded with metal ions. Common examples include calcite and dolomite.
– Oxides: Oxides are minerals containing oxygen and one or more other elements. Common examples include hematite and magnetite.
– Halides: Halides are minerals containing halogen ions (e.g., chloride, fluoride). Common examples include halite (salt) and fluorite.
– Sulfates: Sulfates are minerals containing sulfate ions (SO4^2-). Common examples include gypsum and barite.
– Sulfides: Sulfides are minerals containing sulfur ions bonded with metal ions. Common examples include pyrite and galena.
– Native minerals: Native minerals are elements that exist in pure form. Common examples include gold, silver, and copper.
18. As You Move from Independent to the Framework, Does it Get More or Less Complex?
– Generally, as you move from independent tetrahedra to frameworks, the complexity increases due to the greater interconnectedness of atoms within the crystal structure.
19. What Minerals Are Associated with Continental Crust?
– Common minerals associated with continental crust include quartz, feldspar, and mica.
20. What Minerals Are Associated with Oceanic Crust?
– Common minerals associated with oceanic crust include basalt, gabbro, and olivine.
21. What Minerals Are Common in the Lower Mantle?
– Minerals common in the lower mantle include perovskite and bridgmanite.
22. What Minerals Are Associated with the Upper Mantle?
– Common minerals associated with the upper mantle include olivine, pyroxene, and garnet.
23. What Do We Suspect the Core is Composed Of?
– The Earth’s core is believed to be composed mainly of iron and nickel.
24. What Are the Most Common Elements in the Earth’s Crust?
– The most common elements in the Earth’s crust are oxygen, silicon, aluminum, and iron.
25. What Are the Most Common Elements in the Entire Earth?
– The most common elements in the entire Earth are iron, oxygen, silicon, and magnesium.
26. What Are the Most Common Elements in the Entire Universe?
– The most common elements in the entire universe are hydrogen and helium.
27. What Are Atoms?
– Atoms are the basic building blocks of matter, consisting of a nucleus of protons and neutrons surrounded by electrons.
28. What Are Electrons, Protons, and Neutrons?
– Electrons are negatively charged particles found in orbit around the nucleus of an atom. Protons are positively charged particles found in the nucleus, and neutrons are neutral particles also found in the nucleus.
29. What Are Electron Shells?
– Electron shells are energy levels or regions around an atom’s nucleus where electrons are likely to be found.
30. Gaining Electrons Will Give You What Kind of Charge? Losing Electrons Will Give You What Kind of Charge?
– Gaining electrons will give an atom a negative charge, while losing electrons will give it a positive charge.
31. How Are Elements Organized on the Periodic Table?
– Elements on the periodic table are arranged in order of increasing atomic number and grouped according to similar chemical properties.
32. What Do Rows Have in Common? What Do Columns Have in Common?
– Rows (periods) have elements with the same number of electron shells, while columns (groups) have elements with similar chemical properties due to having the same number of valence electrons.
33. What is the Atomic Number? What is the Atomic Weight?
– The atomic number is the number of protons in the nucleus of an atom. Atomic weight is the average mass of an atom of an element, taking into account the relative abundances of its isotopes.
34. How Do You Know How Many Protons an Element Has?
– The number of protons in an element is equal to its atomic number, which is listed on the periodic table.
35. What is a Covalent Bond? Give an Example of a Mineral That Forms a Covalent Bond.
– A covalent bond forms when atoms share pairs of electrons. Example: Diamond (carbon atoms bonded together via covalent bonds).
36. What is an Ionic Bond? Give an Example of a Mineral That Forms an Ionic Bond.
– An ionic bond forms when one atom donates an electron to another atom, resulting in oppositely charged ions that are attracted to each other. Example: Halite (sodium chloride).
37. What is a Metallic Bond?
– A metallic bond forms when electrons are shared among a lattice of metal atoms, allowing for the free movement of electrons throughout the structure.
38. What is Hydrogen Bonding?
– Hydrogen bonding is a type of weak chemical bond that occurs between hydrogen atoms and electronegative atoms such as oxygen or nitrogen.
39. How Does Water Dissolve Minerals? Under What Circumstances Do Minerals Precipitate from Water?
– Water dissolves minerals by surrounding individual ions and pulling them away from the mineral surface. Minerals precipitate from water when the concentration of dissolved ions exceeds their solubility limit, often due to changes in temperature, pressure, or chemical composition.