Feldspar minerals have very similar structures, chemical compositions, and physical properties. Anne M. Chaka, in Chemical Bonding at Surfaces and Interfaces, 2008. Appearance: White fine powder: Sp. It has some resemblance to anorthite, and it has four distinct polymorphs. Keefer K D, Brown G E (1978) Crystal structure and composition of sanidine and high albite in cryptoperthitic intergrowth Note this sample of feldspar is from the Rabb Canyon pegmatite, Grant County, New Mexico, USA American Mineralogist 63 1264-1273: 1978: 0: 293: 0001125: Sanidine Feldspar Chemical Properties/Composition. 2.3 Dissolution mechanisms at feldspar–water interfaces. Common feldspars include orthoclase (KAlSi 3 O 8), albite (NaAlSi 3 O 8), and anorthite (CaAl 2 Si 2 O 8). To appreciate the importance of feldspar as a rock-forming mineral, let’s consider its abundance in Earth’s crust. The sequence of minerals along the base of the triangle represents the solid solution series of plagioclase between albite and anorthite. Feldspar Chemical composition : Potassium, sodium and calcium-aluminum silicates. The series ranges from albite to anorthite endmembers (with respective compositions NaAlSi3O8 to CaAl2Si2O8), where sodium and calcium atoms can substitute for each other in the mineral’s crystal lattice structure. It forms part of the feldspar group and belongs to the celsian-hyalophane series and the celsian-orthoclase series. in chemical composition of the feldspars, a ternary composition diagram is needed with two independent composition axes and three end member components: Or, Ab, and An (see at-tached diagram). There are different types of feldspar, depending on their composition..It is a common flux material and widely it is used in ceramic industries. Note that the feldpsar compositions follow closely two sides of the composi- tion triangle and that the observed proportion of a third component increases with increasing temperature. I. K-feldspar (KALSi 3 0 8) II . Feldspar is a group of minerals that are found widely throughout the earth’s crust, making up portions of the igneous, sedimentary and metamorphic rock found within the earth. Al2O3: 18±1%: SiO2: 70±2%: Fe2O3: 0.1±0.03%: MgO: 1.0%: Na2O: 3% TO 10%: K2O: 3% TO 12%: CAO: 1±0.3% Feldspar Physical Properties. Composition. Celsian is a barium feldspar with a chemical composition BaAl 2 Si 2 O 8. This diagram shows how feldspar minerals are classified on the basis of their chemical composition. The essential elements are silicon, aluminum, oxygen, and barium. Plagioclase is a continuous series of solid solutions known as the plagioclase feldspar series, rather than a specific mineral with a particular chemical composition.