Hello everyone, this is the novice geologist, and welcome to my first video- ever! 
This is a channel, where learning about our home planet, the Earth, is made fun, and easy.
Let’s get started. 
Today, we’re going to talk about rocks, and minerals. 
They say, a good geologist is one, who has seen the most number of rocks. 
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Today, we’ll be discussing a few basic things about the building blocks of rocks, - minerals.
The branch of Earth Sciences that deals with the composition, structure, appearance, stability, occurrence, and associations of minerals (basically everything about minerals) 
is called Mineralogy. 
Let’s jump into the first question that arises- what is a mineral?
A mineral is a naturally occurring, homogenous, solid, crystalline substance, usually inorganic, with a specific chemical composition.
Now let’s see, what each of the words mean.
Naturally occurring: To qualify as a mineral, a substance must be found in nature.
The diamonds mined in South Africa, for example, are minerals. The synthetic versions produced in industrial laboratories, on the other hand, are not. 
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Nor is any laboratory product invented by chemists.
Homogenous: Means they cannot be divided mechanically into smaller, chemically distinct components.
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That is, it has the same physical and chemical properties throughout.
Solid crystalline substance: Minerals are solid substances— they are neither liquids nor gases. 
To qualify as a mineral, a substance has to be solid first, and then the other things that we’re going to discuss. 
When we say that a mineral is crystalline, it means that the crystal that we’re looking at in our hand, 
looks the same way down to the molecular scale. 
The atoms of the mineral are arranged in an orderly, repeating, three-dimensional array.
Solid materials that have no such orderly arrangement are referred to as glassy or amorphous (without form) 
and are not conventionally called minerals.
Windowpane glass is such an example. 
Usually inorganic: Minerals are defined as inorganic substances and so exclude the organic materials that make up plant and animal bodies.
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Thus, coal, which may have a definite composition and array and is naturally occurring,
will not qualify as a mineral because it is made up of decaying vegetation and other organic materials.
Then what exactly is coal, if not a mineral? A rock? If yes, then what kind of a rock? Let me know in the comments below!
And last but not the least- a specific chemical composition:
The key to understanding the composition of Earth materials, lies in knowing how the chemical elements are organized, into minerals. 
What makes each mineral unique, is its chemical composition and the arrangement of its atoms, in an internal structure. 
Although not always fixed, the composition of a mineral may vary, within certain limits. 
Let’s say for example, the mineral quartz, has a fixed ratio of two atoms of oxygen, to one atom of silicon. 
This ratio never varies, even though quartz is found in many different kinds of rocks.
On the other hand, in the mineral olivine, composed of iron, magnesium, oxygen, and silicon-
the ratio of iron and magnesium almost always varies in every ratio possible, within the permitted limit.
Now that we know what a mineral is, let’s jump in to the next question- 
How do minerals form?
Minerals form by the process of crystallization, in which the atoms of a gas or liquid come together,
in the proper chemical proportions and in the proper arrangement, to form a solid substance. 
The bonding of carbon atoms in diamond, a covalently bonded mineral, is one example of crystallization.
Under the very high pressures and temperatures in Earth’s mantle, carbon atoms bond together in a definite fashion,
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building up a regular three-dimensional structure from a great many atoms. 
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As a diamond crystal grows, it extends its structure in all directions, always adding new atoms in the proper geometric arrangement.
Another example is, salt- The sodium and chloride ions that make up sodium chloride, 
an ionically bonded mineral, also crystallize in an orderly three-dimensional array.
But how do all of these, really happen?
Lowering the temperature of a liquid below its freezing point, is one way to start the process of crystallization.
Magma, a mass of hot, molten liquid rock-
crystallizes into solid minerals, when it cools.
Crystallization can also occur as liquids evaporate from a solution. 
Let’s take salt solution, for example. 
As the water evaporates from a salt solution, the concentration of salt eventually gets so high, that the solution can hold no more salt,
and is said to be saturated.
If evaporation continues, the salt starts to precipitate, as crystals. 
Deposits of table salt, or halite, form under just these conditions when seawater evaporates, to the point of saturation.
And thus forms a mineral- a beautiful creation of nature, and the building block of rocks that eventually make up a whole planet.
Now that you know what minerals are and how they form, stay tuned to the channel for more videos that will follow the topic.
See you around!
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