Chapter 4- Minerals Flashcards
What is a mineral?
A mineral is a naturally occurring inorganic solid with a specific chemical composition and definite crystalline structure.
What are the 3 characteristics that minerals all possess?
Naturally occurring and inorganic, solids with specific composition, and definite crystalline structure.
What does naturally occurring and inorganic mean?
- formed by natural process
- they aren’t alive and never were alive during any part of their existence
What does solids with specific compositions mean?
- solids have definite shapes and volume, liquids and gases do not, so no liquid or gas can be considered a mineral
- each type of mineral has a chemical composition unique to that mineral
- some such as copper, silver, and suffer are composed of single elements but the vast majority are composed of compounds
- in some minerals chemical composition may vary within a certain range
What does definite crystalline structure mean?
- atoms in minerals are arranged in regular geometric patterns that are repeated again and again
- at times a mineral will form in an open space into one large crystal
- more commonly the internal atomic arrangement of a mineral is not so readily available because the mineral formed in a restricted space.
What are the different ways minerals form?
Magma and solution
How do minerals form from magma?
When magma cools as it is forced upward into cooler layers of earths interior, the compounds in magma no longer move freely and begin to interact chemically to form minerals. The type and amount of elements present in the magma help determine which minerals will form. The rate the magma cooks determines the size of the mineral crystal. Magma that cools slowly gives the atoms time to arrange into large crystals while magma that cools quickly will have small crystals.
How fo minerals form from a solution?
A given volume of water can only dissolve so much if a solid before the water becomes saturated. The saturated water can then not dissolve any more solids. If a solution becomes over saturated with another mineral crystals may begin to precipitate. Minerals can also form when elements dissolve in a supersaturated solution. When liquid evaporates from the solution, the elements remain behind and may begin to arrange into crystals.
What are the three main mineral groups?
Silicates, carbonates, and oxides
What are silicates?
Minuerals that contain silicon a X oxygen and usually one or more other elements. They make up approximately 96% of the minerals found on Earth’s crust. The basic silica tetrahedron has the ability to share O2 molecules chemically which accounts for the vast majority of silicates.
What are carbonates?
Minerals composed of one or more metallic elements with the carbonate compound CO3. Carbonates are the primary compound in rocks such as limestone. Some have distinctive colourations.
What are oxides?
Compounds of oxygen and metal. Hematite and magnetite are common iron oxides and good sources of iron. Uraninite is valuable because it is a good source of uranium. Other major mineral groups are sulfides, sulfates, halides, and native elements such as silver (native elements are made of only one element).
Why is petroleum not a mineral?
It comes from organic material and is a liquid.
What are the two most abundant elements found in Earth’s crust? Which mineral group are they ?
Oxygen and silicate from the mineral group silicates.
What is a crystal?
A crystal is a solid in which the atoms are arranged in a repeating pattern. What determines the size of a mineral crystal formed by magma us how fast or slow the magma cools. Small crystals form from rapidly cooling magma and large crystals form from slowly cooling magma.
