Less common minerals

Representative propylitie alteration minerals inelude epidote, albite, earbonates, quartz, chlorite, sericite, and smectite. The less common minerals are mixed-layer elay minerals such as chlorite/smectite and sericite/smectite and zeolite minerals. 

We begin with a discussion of the most common minerals present in Earth s crust, soils, and troposphere, as well as some less common minerals that contain common environmental contaminants. Following this is (1) a discussion of the nature of environmentally important solid surfaces before and after reaction with aqueous solutions, including their charging behavior as a function of solution pH (2) the nature of the electrical double layer and how it is altered by changes in the type of solid present and the ionic strength and pH of the solution in contact with the solid and (3) dissolution, precipitation, and sorption processes relevant to environmental interfacial chemistry. We finish with a discussion of some of the factors affecting chemical reactivity at mineral/aqueous solution interfaces. 

Common minerals in Earth s crust, soils, and atmosphere, weathering mechanisms and products, and less common minerals that contain or adsorb environmental contaminants... 

Most of the heavy metal contaminants associated with mining or agricultural practices are released from less common mineral phases, some of which are primary (i.e., formed initially by an igneous, metamorphic, or sedimentary process) and some of which are secondary (i.e., formed by chemical alteration of the primary minerals). Table 7.4 lists some of the more common contaminant ions and the mineral phases with which they are associated in economic mineral deposits or weathered zones associated with these deposits. 

Examples of less common minerals that contain common environmental contaminants and their relative solubilities or ease of removal of adsorbed species. 

Cyclosilicates are those compounds with three or more tetrahedra linked in closed, ring-like structures. The ratio between Si and O is 1 3. This group includes the important gem species beryl and the tourmaline group. The 11 members of the tourmaline group display an unusual property known as piezoelectricity. When pressure is applied to a crystal, an electrical charge builds up at either end of it. This makes these minerals useful in pressure gauges and other electrical equipment. Quartz and a few other, less common minerals, also display this property. 

In the course of time, incompletely investigated minerals may require reallocation in lire system. Similarly, the occasional discredited mineral name may have to be revalidated. Such changes, however, will generally be restricted to the less common minerals, and those that can easily be shifted in collections. Because of the large volume of material in this volume, the occasional literature reference may be overlooked. The author would therefore appreciate all contributions from his professional colleagues and friends of mineralogy. 

The most common minerals in coal (e.g., ilUte clay, pyrite, quartz, and calcite) are made up of these most common elanents (in rough order of decreasing abundance) oxygen, aluminum, silicon, iron, sulfur, and calcium. These minerals and other less common minerals usually contain the bulk of the trace elanents present in coal (Finkelman, 1982,1993 Davidson and Clarke, 1996 Davidson, 2000). 

Magnesium oxide is a white powder broadly similar to calcium oxide and is rarely found in Nature as such but more commonly as the carbonate form, including the less common mineral complex with calcium carbonate (carnalhte) [5]. 

Igneous rocks are essentially composed of the six major rock forming silicate minerals (i.e., they constitute about 95% of all igneous rocks), which include peridots, pyroxenes, amphi-boles, feldspars, micas, and quartz. Other minerals may also be present, but they usually make up only a small fraction of the rock. These less abundant and less common minerals... 

Less common minerals Rutile, titanite, apatite, beryl, tourmaline, zircon... 

The most abundant Zr mineral is zircon, ZrSi04, a tetragonal orthosilicate, frequently found in a prismatic, pyramidal habit, with Zr coordinated to eight oxygen atoms. A relatively common oxide is baddeleyite, Z1O2, a monoclinic mineral found in prismatic habit Other less common minerals are calzirtite, CaZrjTiO, and zirconolite, CaZrjTijOy, where zirconium appears associated with calcium and titanium. All these minerals can be found as primary or secondary. Hafnium is a common substituent for Zr, and rare earths such as yttrium are also found. 

The most common ores of rubidium are le-pidolite, carnallite, and pollucite. Rubidium is also found in seawater and in mineral springs. 

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