Rocks are composed of minerals that have a specific chemical composition. As is discussed in later chapters, there are three types of rocks composed of minerals: igneous (rocks crystallizing from molten material), sedimentary (rocks composed of products of mechanical weathering (sand, gravel, etc.) and chemical weathering (things precipitated from solution), and metamorphic (rocks produced by alteration of other rocks by heat and pressure. Typically, substances like coal, pearl, opal, or obsidian that do not fit the definition of mineral are called mineraloids.Ī rock is a substance that contains one or more minerals or mineraloids. But once that clam shell undergoes burial, diagenesis, or other geological processes, then the calcite is considered a mineral. Because of these discrepancies, the International Mineralogical Association in 1985 amended the definition to: “A mineral is an element or chemical compound that is normally crystalline and that has been formed as a result of geological processes.” This means that the calcite in the shell of a clam is not considered a mineral. Calcite is quite often formed by organic processes, but is considered a mineral because it is widely found and geologically important. Both are considered minerals because they were classified before the room-temperature rule was accepted as part of the definition. For example, water and mercury are liquid at room temperature. Some natural substances technically should not be considered minerals, but are included by exception. In geology, the classic definition of a mineral is: 1) naturally occurring, 2) inorganic, 3) solid at room temperature, 4) regular crystal structure, and 5) defined chemical composition. The term “minerals” as used in nutrition labels and pharmaceutical products is not the same as a mineral in a geological sense. Identify minerals using physical properties and identification tables.List common non-silicate minerals in oxide, sulfide, sulfate, and carbonate groups.Describe the silicon-oxygen tetrahedron and how it forms common silicate minerals.Describe chemical bonding related to minerals.Derive basic atomic information from the Periodic Table of Elements.Describe the basic structure of the atom.The largest crystal found here is 39 feet (12 meters) and 55 tones.Īt the end of this chapter, students should be able to: to balance it will need, one Ca 2+ ion and two OH - ions,ĭeduce the formula for sodium carbonate.These selenite (gypsum) crystals, found in The Cave of the Crystals in Naica, Mexico, has some of the largest minerals ever found.this is two positive charges and one negative charge.ExampleĬalcium hydroxide contains Ca 2+ and OH - ions: If more than one polyatomic ion is needed, its formula is written inside brackets. The formulae of compounds containing polyatomic ions are worked out in a similar way to single atom ions. The table shows the names and formulae of some of these ions.
Polyatomic ions are formed from groups of atoms. The table shows the formulae of some common transition metal ions. The number in the name of the compound shows the charge of the metal ions in that compound.įor example, copper(II) sulfate contains Cu 2+ ions. Transition metals (in the central block between groups 2 and 3) can have ions with different charges. Elements in the same group form ions with the same charge. The charge of many ions can be worked out using patterns in the periodic table.
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