Minerals in the soil and in the rocks!

        Going back, previous lessons in ELS were about Earth’s habitability and its subsystems. We are now moving on from these lessons to minerals! A part of one of the subsystems, the geosphere, minerals make up the soil and rocks from the surface of the Earth to the deep rocks in the mantle. Let's dive into the minerals' 

        The building blocks of rocks, for a mineral to be considered a mineral, we learned that they should have to have these five characteristics: (1) formed by natural processes, (2) inorganic, (3) homogeneous solid, (4) definite chemical composition, and (5) orderly crystalline structure. Also, minerals form in 2 ways: (1) evaporation of water that has minerals dissolved in it and (2) the cooling of hot, liquid rock called magma causes compounds to combine. 

        Minerals have many properties: (1) Color, (2) luster, (3) streak, (4) hardness, (5) crystal form, and (6) cleavage. These refer to the following:

        1. Due to impurities and geologic processes like weathering, minerals’ colors may display a variety of colors.

        2. Luster refers to the quality and intensity of reflected light exhibited by the mineral that may classified into two: metallic (opaque and resplendent shine like a polished metal) and non-metallic (vitreous, adamantine, resinous, silky, pearly, dull, greasy, and the like).

        3. Streak is the color of the mineral in powdered form. A more diagnostic property compared to color which may be different from the color of the mineral.

        4. Hardness measures the minerals’ resistance to abrasion. Mineralogists who study minerals, use the Mohs Scale of Hardness designed by German geologist/mineralogist Friedrich Mohs in 1812. In this scale, a mineral’s hardness is classified from 1-10 where Talc is the softest (1) and Diamond is the hardest (10).

        5. Crystal form/habit is displayed or observed when crystals grow in open space which refers to the external shape of a crystal or groups of crystals. A mineral can be described as amorphous if it does not have a crystal structure.

        6. Cleavage is the property of some minerals to break along specific planes of weakness to form smooth, flat surfaces due to the existing bond of atoms that makes a mineral weak in those areas.

        These qualities were showcased while our teacher, Sir Rolan, was discussing these properties by giving us a case filled with different kinds of rocks. The funny thing is, while we were observing some of the rocks given to us, we smelt a rock that was stinky. We laughed while smelling how bad the smell of the rock was. But nevertheless, it was fun seeing those rocks and learning more about minerals and their properties. Until next time, Ad Astra!