Mineralogy Resource Guide for Kids

You may have used a pencil to write and draw but have you ever wondered what the pencil's lead made of? You have probably seen all those beautiful and sparkling diamonds in jewelry store windows, but do you know where they come from? In reality, the pencil lead and the diamonds are minerals. You have probably heard about minerals but do you know exactly what they are and where do they come from? Let's take a deeper look.

Minerals are defined as naturally occurring substances with a definite chemical formula and general structure. These are inorganic solid substances which are made up of elements. Elements are the simplest of substances which cannot be broken down any further. Almost every element found in the Earth's crust is associated with at least one mineral. Minerals which are made up of one or two elements and they have a simple chemical formula. For instance, salt, also known as sodium chloride, is a combination of sodium and chlorine and the chemical formula is NaCl. On the other hand, minerals which are made up of a large number of elements have complex chemical formulas.

Minerals are important for a variety of reasons. Firstly, they act as raw materials of the metals which are converted into manufactured goods that we use in our daily lives. Some minerals are radioactive so they are used in nuclear reactors while some are magnetic so they are used for different purposes. Precious minerals and gemstones like diamond, gold, and silver are commonly used for making ornaments because of their striking and beautiful colors.

With over 3,000 different types of existing minerals, their classification into various categories can be a nightmare. Although different grouping systems are used by mineralogists, the most widely accepted is the 'Dana System'. In this system, minerals are divided into 8 basic classes as follows:

  • Native Elements: The purest, naturally occurring minerals.
  • Silicates: Minerals made up of metals combined with silicon and oxygen like mica
  • Oxides: Minerals formed by the combination of a metal with oxygen like rubies and sapphires
  • Sulfides: Combination of a metal with sulfur like Pyrite
  • Sulfates: Compounds of sulfur combined with metals and oxygen
  • Halides: Combination of metals with halogens
  • Carbonates: Minerals made up of carbon, oxygen, and a metal
  • Phosphates: Formed by the weathering down of other minerals
  • Mineraloids: Minerals that fall outside of the other mentioned classes.

Assuming that you come across a mineral, how would you identify it? Minerals can most commonly be identified by inspecting or testing their physical characteristics. These physical properties are hardness, transparency, color, luster, cleavage, streak, fracture, crystal form, and specific gravity. Apart from these basic characteristics, some special properties like magnetism and conductivity can also help identify minerals.

The most common mistake that many people make is to confuse rocks with minerals because they have many different varieties and sometimes, they may even look similar. It's important to keep this in mind. While minerals are naturally occurring solids, rocks are an aggregate of one or more minerals. Only a few minerals have the capacity to form rocks. The majority of rocks found on the Earth's crust are composed of minerals like quartz, calcite, and mica. For economic purposes, minerals are also extracted from rocks, known as ores.

The study of minerals is very interesting because you can learn about their properties and uses. Here's a resource guide and further information on mineralogy.

  • Minerals: A comprehensive resource center for many minerals with pictures and descriptions.
  • What is a Mineral?: Here's an overview about minerals.
  • Mining for Minerals: Have some fun and play this game to learn more about minerals.
  • Apatite: It has Mohs Scale of Hardness is 5 and density is 3.1-3.2 g/cubic cm.
  • Augite: The color of this mineral is dark green to black.
  • Biotite: Typically, biotite appears in shades of brown but it can also be in red, green or yellow.
  • Calcite: It has a density of 2.71 g/cubic cm and Mohs Scale of Hardness is 3.
  • Corundum: This mineral can be red, pinkish or brownish-red.
  • Dolomite: The composition of this mineral is calcium and magnesium carbonate.
  • Fluorite: This fluorescent mineral can appear in sea green, deep purple, sky blue, and other colors.
  • Galena: It is a major source of lead ore.
  • Garnet: This silica mineral has Mohs hardness of 6 to 7.5.
  • Graphite: It possesses both metallic and nonmetallic properties.
  • Gypsum: It has a pearly luster and a density of 2.3 g/cubic cm.
  • Halite: This mineral has a Mohs hardness of 2.5 and a white streak.
  • Hematite: The PDF presents some general information on the mineral.
  • Hornblende: Crystals are usually hexagonal but prismatic crystals can be elongated.
  • Magnetite: It has a Mohs hardness of 5.5 to 6.5 and it has no cleavage.
  • Muscovite: This mineral is usually colorless.
  • Olivine: Olive green in color, it has a gravity of 3.27 to 4.20 g/cubic cm.
  • Orthoclase: It has a Mohs hardness of 6 to 6.5 and white streak.
  • Plagioclase: This mineral is usually colorless.
  • Pyrite: It has a metallic luster and its color is brassy yellow.
  • Quartz: A silicone dioxide, this mineral has many colors.
  • Talc: This mineral is non-abrasive with a Mohs hardness of 1.

Content written and provided by Vanessa LeBeau

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