hello grade 11. in this video you will learn about identifying wrap forming minerals using their physical and chemical properties [Music] our discussion will focus on the learning competency identify common rock-forming minerals using their physical and chemical properties do you consider water as a mineral how about tube ice or snowflakes are these minerals minerals are the fundamental components of rocks they are naturally occurring inorganic solid with an orderly crystalline structure in a definite chemical composition [Music] therefore water is not a mineral because it is not solid in crystalline tube ice is also not a mineral because it is not naturally occurring but a snowflake possesses all the properties under the definition of a mineral now let's discuss the physical and chemical properties of rock forming minerals let's start with luster this refers to the way light is reflected from the surface of a mineral types of luster we have the metallic and the non-metallic examples are metallic cluster pyrite and non-metallic plaster kaolinite next is hardness it is a measure of the resistance of a mineral to scratch the most scale of hardness measures the scratch resistance of various minerals from a scale of one to ten with dark as the softest and diamond as the hardest mineral this was designed by mineralogist friedrich moss next is color minerals display a variety of colors resulting from impurities and also from geologic processes like weathering examples of coloring azerite is purple sulfur is yellow we also have strict minerals color in powdered form streak is a more reliable property than color because street does not vary minerals that have the same color may have different colored strip example is this one the hematite next is the crystal form or habit it is the natural shape of the mineral before the development of any cleavage or fracture we also have cleavage the property of some minerals to break along specific planes of weakness to form smooth flat surfaces minerals that do not exhibit cleavage are said to fracture when broken some break leg glass some into splinters or fibers last is the specific gravity which is the ratio of the density of the mineral and the density of water measured based on the amount of water displaced to determine chemical properties sample chemical test is done for example order taste and reaction to assay the most stable and least ambiguous basis for classification of minerals is based on their chemical compositions silicate for example is a mineral containing the two most abundant elements in the earth's crust namely silicon and oxygen over 90 percent of rock forming minerals belong to this group we also have oxides sulfates sulfides carbonates the native elements and the halites now let's talk about the common wrap forming minerals first we have quartz quartz is usually called silica it is made up of silicon dioxide which is the raw material for making glass next we have plagioclase feldspar which is an important industrial mineral used in ceramics next we have alkali feldspar it is commonly pink to white used as a raw material to make porcelain we also have micas micas are family of silicate minerals they are common materials in intrusive igneous rocks and also found in sedimentary we also have the amphiboles are a family of silicate minerals they are a component of many igneous and metamorphic we also have pyroxene these crystals are commonly faceted as gemstones for instance precious chain is a pyroxene next is all divine a silicate mineral clear and transparent olivine crystals are commonly faceted as gemstones last is calcite calcite is the major component of calculus sedimentary rocks such as limestone metamorphism produces marble and that's it now let's check your understanding direction identify the properties of rock-forming minerals described in the following one refers to the way light is reflected from the surface of a mineral answer that's correct luster two minerals color in powdered form answer very good strict number three it is a measure of the resistance of a mineral to scratch there you have it hardness and that's the end of our lesson congratulations [Music] you