Rocks and Minerals

Your school building, residential complex, etc. consists of rocks and minerals.   Furthermore, the planet earth is a treasure chest of rocks and minerals.    Have you ever wondered how rocks are different from minerals?  They are ingenious parts of our routine life.  Cement, gold, granite, pumice, etc. are a few examples of the rocks and minerals that we use in our daily life.  People use the term ‘rocks and minerals’ synonymously.  They are not able to distinguish between rocks and minerals because they do not know their meaning. However, it is essential to understand that there is a difference between rocks and minerals.  Let us discuss rocks and minerals and their meanings.


What are Minerals? 

Nature is the creator of minerals.  Minerals are naturally occurring solid substances that have a fixed chemical composition.  Their inorganic structure has a crystalline form and shape.  The presence of iron, calcium, potassium has traces in the food we eat.  There are two types of minerals – metallic and non-metallic.  Examples of Metallic minerals are magnetite and bauxite.  Mica, quartz, calcite, gypsum are excellent examples of non-metallic minerals. 

 

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What are Rocks? 

A rock is a hard substance, inorganic in nature.  Similar to minerals, the formation of rocks is a natural process.  However, it may be interesting to know that rock is a composition of two or more mineral grains.  In other words, a rock is a mineraloid matter or mineral rock.  Rocks have different shape, size, and texture.  Geologists have categorized rocks into three types  – igneous, sedimentary, and metamorphic rocks.  For excellent examples are sandstone, limestone, marbles, slate, etc. 


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Here is an overview that will help you understand the difference between rocks and minerals if you are still confused about how to differentiate between rocks and minerals.

Rocks and Minerals Difference


What is the Difference Between Rocks and Minerals?


S.No.

ROCKS

MINERALS

1

Rocks contain minerals.

Minerals do not contain rocks.

2

Some rocks are microscopic.

You can easily recognize the nature of minerals.

3

About 90 - 95% of the earth’s crust is made up of igneous and metamorphic rocks.

Mineral deposits occur naturally formed on the earth.

4

Rocks are not edible.

Minerals are edible. Eg. Salt.

5

There is neither atomic structure nor chemical composition of rocks.

Minerals basically have a specific chemical composition.

6

Rocks are available in various shapes, size, and colours.

Minerals have a definite shape, and colour.

7

Some examples of rocks are sandstone, limestone, marble, slate, etc.

Some examples of minerals are bauxite, magnetite, mica, gypsum, etc.

 


What are the Various Uses of Rocks and Minerals?


What are the Uses of Rocks?

  1. Generating electricity, power, and heat

The sedimentary rock, coal, is combustible.  It is a fossil fuel used for cooking, heating, producing electricity, and running steam engines.  Petroleum is also a fossil fuel.  You can commonly use it as petrol, diesel, kerosene, gasoline, and LPG.

  1. Construction

Builders use sandstone, granite, limestone, and marble extensively to build statues, domes, and monuments. Pumice is used for bathing, building lightweight concrete blocks.  Paper, petrochemicals, insecticides, fiberglass, glass, etc. are the product of limestone.


What are the Uses of Minerals?

  1. Fertilizer

Sulphates and nitrates are added as fertilizer to the soil.

  1. Health and Medicine

Calcium, iron, and sodium are essential minerals needed for good health.

  1. Building Materials

Gypsum and Calcite help in making mortar, cement, and concrete.

  1. Gemstone

Diamond, ruby, emerald, topaz, and sapphire make attractive ornaments.

 

Chemical Composition of Rocks and Minerals

Rocks are made from a variety of compounds in different percentages by mass. The proportions of each compound impart the rock its properties. In granite, the primary component is of silica i.e., 72.04%.


You can classify minerals as pure elements, simple compounds, and complex compounds.  Simple compounds are composed of more than two or two atoms in definite proportions, such as water(H2O), carbon dioxide(C02), etc.  Complex compounds are substances where there is the bond formation between both metals and nonmetals like Steenstrupine- 

Na14Ce6Mn2+Mn3+Fe2+5(Zr,Th)(SO18)2(PO4)7⋅3H2ONa14Ce6Mn2+Mn3+Fe52+(Zr,Th)(SO18)2(PO4)7⋅3H2O.

 

Some Fascinating and Fun Facts on Rocks and Minerals

  1. Did you know that the talcum powder is a mineral?  Talcum powder that you use after shower is made from the softest mineral, talc.

  2. The monumental Taj Mahal is made up of marble, a kind of rock.   Some gemstones are also embedded as decoration.

  3. You all know that rock has a high density, and it sinks in water.  However, pumice being a rock floats in water.

FAQ (Frequently Asked Questions)

Q1. Why can’t we Classify Rock Salt as a Rock?

A1. Rock salt is a perfect ingredient in every salty food.  It is classified as a mineral irrespective of the name, rock salt because it is a crystalline mineral.  The crystals of the salt are translucent.  You can abundantly find it in seawater where the mineral composition is the highest.   It is a compound of two chemicals - sodium chloride.  The standard formula for salt is (NaCl). Furthermore, when you add water to this chemical compound, the ions of Na+ and Cl- separate.  Hence, salt is soluble in liquid.  About 359 grams of salt can be dissolved quickly in one litre of water.

Q2. Pumice is Stone, then why Doesn’t it Sink?

A2. The scientific name of the fine grains of pumice stone is pumicite.  It is initially in a dust form or a powdered form.  It is formed naturally from the eruptions of explosive underwater volcanoes.  Thus, you can find it near continental volcanic and submarine volcanic occurrences. The extremely hot erupted-volcanic matter rapidly cools down at the surface than its interior under depressurization. Thus, bubbles of air are trapped inside it. The hot interior gradually solidifies to form a rock filled with millions of air bubbles, which we call pumicite. Thus, making it is highly porous and vesicular.  The tiny pores in the pumice rock are hollow.  It becomes a lightweight rock.  The density of water is heavier than a pumice stone.  Thus, it floats in water.