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Igneous Petrology and the Nature of Magmas
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
Different minerals melt at different temperatures. Ice, for example, melts when the temperature reaches 0 °C (32 °F) at one atmosphere pressure, but gold—shown melting in Figure 5.34—melts at 1064 °C, equivalent to 1948 °F. Many minerals melt at temperatures above the melting temperatures for ice and gold. Quartz, for example melts at 1670 °C at one atmosphere pressure, and Mg-olivine (forsterite) melts at 1890 °C. When ice, gold, quartz, or forsterite melt, the composition of the melt is the same as the solid. Thus, ice melts to produce water, molten gold has the same composition as solid gold, molten quartz is SiO2, and molten forsterite is Mg2SiO4. The temperatures at which melting occurs for ice, gold, quartz, and olivine—0 °C, 1064 °C, 1670 °C, and 1890 °C——are the minerals’ melting points. Because ice, gold, quartz, and forsterite all have a single melting point, if they are subjected to heating, temperature will not increase above the melting point until all the solid has become liquid. At higher temperatures, all will be liquid; at lower temperatures, all will be solid.
Crystal Chemistry and Specific Crystal Structures
Published in David W. Richerson, William E. Lee, Modern Ceramic Engineering, 2018
David W. Richerson, William E. Lee
The [olivine] structure is named after the mineral olivine, (Mg, Fe)2SiO4, which is a solid solution between the minerals forsterite (Mg2SiO4) and fayalite (Fe2SiO4). The structure consists of a slightly distorted, hexagonal, close-packed anion arrangement with the smaller “B” cations positioned in one-eighth of the tetrahedral interstitial sites and the larger “A” cations in half of the octahedral sites.
Minerals
Published in W.S. MacKenzie, A.E. Adams, K.H. Brodie, Rocks and Minerals in Thin Section, 2017
W.S. MacKenzie, A.E. Adams, K.H. Brodie
Olivine is the name given to the solid solution series between forsterite (Mg2SiO4) and fayalite (Fe2SiO4). It is recognized in thin section by its high relief and high birefringence and the fact that it very rarely shows a good cleavage but is commonly traversed by randomly orientated cracks (often containing serpentine formed from the low temperature hydration of the olivine). Figure 30 and Figure 31 show a peridotite composed almost entirely of olivine. Figure 32 & Figure 33 show phenocrysts of olivine in a fine-grained groundmass containing pale brown pyroxene crystals and small lath-shaped plagioclase feldspars with grey or white interference colours. The individual crystals of olivine show different interference colours because they represent different orientations of cutting of the crystals, so they may show first-, second-, or third-order colours. In Figure 33 zoning of the larger olivine crystals is shown by the difference in the interference colours between the main part of the crystals and the rims—the rims are slightly different chemically, being richer in iron.
Insight into the partial replacement of cement by ferronickel slags from New Caledonia
Published in European Journal of Environmental and Civil Engineering, 2022
Manal Bouasria, Laidi Babouri, Fouzia Khadraoui, Daniel Chateigner, Stéphanie Gascoin, Valérie Pralong, Mohammed-Hichem Benzaama, Beate Orberger, Yassine El Mendili
Raman spectroscopy analyses confirm that the FNS slags are polycrystalline and heterogeneous whose main components are amorphous silica (SiO2), quartz (SiO2), forsterite (Mg,Ni)2SiO4) and enstatite (Mg,Fe)2SiO3 with some traces of Akaganeite (β-FeO1 – 2x(OH)1 +xClx), chromite (FeCr2O4), calcite (CaCO3; Figures 6 and 7). Forsterite is a highly stable mineral with a melting point of 1890 °C (Kosanović et al., 2005; Maghsoudlou et al., 2016). It is known that periclase (MgO) reacts with amorphous silica at temperatures above 900 °C to form forsterite (Kosanović et al., 2005). In the presence of high quantity of quartz and silica, forsterite reacts with SiO2 to form enstatite (Michel et al., 2014).
Impact of forsterite addition on mechanical and biological properties of composites
Published in Journal of Asian Ceramic Societies, 2020
Rajan Choudhary, Senthil Kumar Venkatraman, Inna Bulygina, Ankita Chatterjee, Jayanthi Abraham, Fedor Senatov, Sergey Kaloshkin, Artem Ilyasov, Maxim Abakumov, Marina Knyazeva, Dimitri Kukui, Frank Walther, Sasikumar Swamiappan
Forsterite (Mg2SiO4) is a dimagnesium silicate with superior mechanical properties over calcium phosphates and calcium magnesium silicates. In addition, forsterite is a biocompatible material that possesses HAp deposition ability and stimulates proliferation and adhesion of osteoblasts [10]. The influence of forsterite content on the mechanical properties and apatite formation ability of bioglass/forsterite composites was studied [18]. It was also observed that an increase in forsterite content in the composite plays a key role in enhancing mechanical strength as well as apatite deposition on the surface of the composites. Later, Sebdani and Fathi (2012) coated HAp/bioglass/forsterite composites on 316 L stainless steel implant. An increase in apatite deposition with the increase in forsterite concentration indicates that it can be used as a potential bioceramic in hard tissue regeneration [19].
Rice husk/rice husk ash as an alternative source of silica in ceramics: A review
Published in Journal of Asian Ceramic Societies, 2018
SK S. Hossain, Lakshya Mathur, P.K. Roy
Crystalline magnesium silicate, which is known as forsterite, has the chemical formula Mg2SiO4. It has a high melting point (1890ºC), high chemical durability, good insulation properties, a low dielectric constant, low electrical conductivity and very low thermal conductivity, which make it a potential material for use in dielectric substrates [87], pigments [88], refractory materials [89], etc. Since forsterite is a part of the MgO-SiO2 system, RHA can be used as a source of silica for its preparation. Mathur et al. [90] prepared nanocrystalline forsterite using RHA as a silica source by a solid-state method. In their study, they observed that some secondary phase of forsterite occurs at below 1000ºC but that the pure forsterite phase is obtained at 1000ºC. This formation of forsterite at 1000ºC can be attributed to the diffusion of magnesia in the enstatite or clinoenstatite phases, which are formed at low temperatures.