{"id":179,"date":"2018-03-25T01:44:18","date_gmt":"2018-03-25T05:44:18","guid":{"rendered":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/chapter\/5-3-mineral-groups-2\/"},"modified":"2026-02-06T13:08:41","modified_gmt":"2026-02-06T18:08:41","slug":"mineral-groups","status":"publish","type":"chapter","link":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/chapter\/mineral-groups\/","title":{"raw":"5.3 Mineral Groups","rendered":"5.3 Mineral Groups"},"content":{"raw":"Minerals are organized according to the anion or anion group (a group of atoms with a net negative charge, e.g., SO4<\/sub>2\u2013<\/sup>) they contain, because the anion or anion group has the biggest effect on the properties of the mineral.\u00a0 Silicates, with the anion group SiO4<\/sub>4-<\/sup>, are by far the most abundant group in the crust and mantle. (They will be discussed in Section 5.4). The different mineral groups along with some examples of minerals in each group are summarized below.\r\n

Oxide Minerals: O2-<\/sup> Anion<\/h1>\r\nOxide<\/strong> minerals (Figure 5.14) have oxygen (O2\u2013<\/sup>) as their anion.\u00a0 They don't include anion groups with other elements, such as\u00a0 the carbonate (CO3<\/sub>2\u2013<\/sup>), sulphate (SO4<\/sub>2\u2013<\/sup>), and silicate (SiO4<\/sub>4\u2013<\/sup>) anion groups. The iron oxides hematite and magnetite are two examples that are important ores of iron. Corundum is an abrasive, but can also be a gemstone in its ruby and sapphire varieties. If the oxygen is also combined with hydrogen to form the hydroxyl anion (OH\u2013<\/sup>), the mineral is known as a hydroxide<\/strong>. Some important hydroxides are limonite and bauxite, which are ores of iron and aluminum, respectively.\r\n\r\n[caption id=\"attachment_172\" align=\"aligncenter\" width=\"650\"]\"\" Figure 5.14 <\/strong>Oxide minerals include metal ore minerals, industrial minerals, and gemstones. Source: Karla Panchuk (2018), CC BY-NC-SA 4.0. Component photographs by Roger Weller\/Cochise College.[\/caption]\r\n

Sulphide Minerals: S2-<\/sup> Anion<\/h1>\r\nSulphide<\/strong> minerals (Figure 5.15) include galena, sphalerite, chalcopyrite, and molybdenite, which are the most important ores of lead, zinc, copper, and molybdenum, respectively. Some other sulphide minerals are pyrite, bornite, stibnite, and arsenopyrite. Sulphide minerals tend to have a metallic sheen.\r\n\r\n[caption id=\"attachment_173\" align=\"aligncenter\" width=\"650\"]\"Sulphide<\/a> Figure 5.15<\/strong> Sulphide minerals often have a metallic lustre and include metal ores. Source: Karla Panchuk (2018) CC BY-NC-SA 4.0. Photos by R. Weller\/ Cochise College. Click for more attributions.[\/caption]\r\n

Sulphate Minerals: SO4<\/sub>2-<\/sup> Anion Group<\/h1>\r\nMany sulphate<\/strong> minerals form when sulphate-bearing water evaporates. A deposit of sulphate minerals may indicate that a lake or sea has dried up at that location.\u00a0 Sulphates with calcium include anhydrite, and gypsum (Figure 5.16). Sulphates with barium and strontium are barite and celestite, respectively. In all of these minerals, the cation has a +2 charge, which balances the \u20132 charge on the sulphate ion.\r\n\r\n[caption id=\"attachment_174\" align=\"aligncenter\" width=\"650\"]\"\"<\/a> Figure 5.16<\/strong> Sulphate minerals. Source: Karla Panchuk (2018), CC BY-NC-SA 4.0. Click for more attributions.[\/caption]\r\n

Halide Minerals: Anions from the Halogen Group<\/h1>\r\nThe anions in halides<\/strong> are the halogen<\/strong> elements including chlorine, fluorine, and bromine. Examples of halide minerals are cryolite, fluorite, and halite (Figure 5.17).\u00a0 Halide minerals are made of ionic bonds. Like the sulphates, some halides also form when mineral-rich water evaporates.\r\n\r\n[caption id=\"attachment_175\" align=\"aligncenter\" width=\"650\"]\"Halides<\/a> Figure 5.17<\/strong> Halide minerals. Source: Karla Panchuk (2018), CC BY-NC-SA 4.0. Click for more attributions.[\/caption]\r\n

Carbonate Minerals: CO3<\/sub>2-<\/sup> Anion Group<\/h1>\r\nThe carbonate <\/strong>anion group combines with +2 cations to form minerals such as calcite, magnesite, dolomite, and siderite (Figure 5.18). The copper minerals malachite and azurite are also carbonates.\u00a0 The carbonate mineral calcite is the main component of rocks formed in ancient seas by organisms such as corals and algae.\r\n\r\n[caption id=\"attachment_176\" align=\"aligncenter\" width=\"650\"]\"Carbonate<\/a> Figure 5.18<\/strong> Carbonate minerals. Source: Karla Panchuk (2018), CC BY-SA 4.0. Photos by Rob Lavinsky, iRocks.com, CC BY-SA 3.0. Click for more attributions.[\/caption]\r\n

Phosphate Minerals: PO4<\/sub>3-<\/sup> Anion<\/h1>\r\nThe apatite group of phosphate<\/strong> minerals (Figure 5.19, left) includes hydroxyapatite, which makes up the enamel of your teeth. Turquoise is also a phosphate mineral (Figure 5.19, right).\r\n\r\n[caption id=\"attachment_177\" align=\"aligncenter\" width=\"650\"]\"\"<\/a> Figure 5.19<\/strong> Phosphate minerals. Source: Karla Panchuk (2018), CC BY-NC-SA 4.0. Photos by R. Weller\/ Cochise College. Click for more attributions.[\/caption]\r\n

Silicates (SiO4<\/sub>4<\/sup>\u2013<\/sup>)<\/h1>\r\nThe silicate<\/strong> minerals include the elements silicon and oxygen in varying proportions . These are discussed at length in Section 5.4 Silicate Minerals<\/a>.\r\n

Native Element Minerals<\/h1>\r\nThese are minerals made of a single element, such as gold, copper, silver, or sulphur (Figure 5.20).\r\n\r\n[caption id=\"attachment_178\" align=\"aligncenter\" width=\"650\"]\"\"<\/a> Figure 5.20<\/strong> Native element minerals are made up of a single element. Source: Karla Panchuk (2018), CC BY-SA 4.0. Click for more attributions.[\/caption]\r\n\r\n
\r\n\r\nBeginner Practice with Anionic Groups<\/strong>\r\n\r\nMinerals are grouped according to the anion part of the mineral formula, and mineral formulas are always written with the anion part last. For example, in pyrite (FeS2<\/sub>), Fe2+<\/sup><\/sub> is the cation and S\u2013<\/sup> is the anion. This helps us to know that it\u2019s a sulphide, but it isn't always that obvious...\r\n\r\nHematite (Fe2<\/sub>O3<\/sub>) is an oxide; that\u2019s easy, but anhydrite (CaSO4<\/sub>) is a sulphate because SO4<\/sub>2\u2013<\/sup> is the anion, not O. Similarly, calcite (CaCO3<\/sub>) is a carbonate, and olivine (Mg2<\/sub>SiO4<\/sub>) is a silicate.\r\n\r\nMinerals with only one element (such as S) are native minerals, while those with an anion from the halogen column of the periodic table (Cl, F, Br, etc.) are halides.\r\n\r\n[h5p id=\"56\"]\r\n\r\n<\/div>\r\n
\r\n\r\nAnionic Groups: Level Up!<\/strong>\r\n
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  1. Select all of the oxide minerals (O2<\/sub>2\u2212<\/sup>anion).\r\n