Minerals

To be called a mineral, a substance must follow these five rules:

Naturally occurring: It is made by nature, not by people.
Inorganic: It is not made from living things or their remains.
Solid: It is not a liquid or a gas.
Crystalline structure: The atoms inside are arranged in a very tidy, repeating pattern.
Chemical composition: It has a specific recipe or formula. For example, Quartz is always made of Silicon and Oxygen, written as $SiO_{2}$ .

Chemical Elements: Elements are the basic ingredients. Some minerals use only one element, like Gold ( $Au$ ). Others use several, like Table Salt (Halite), which is made of Sodium ( $Na$ ) and Chlorine ( $Cl$ ).
Chemical Bonds: These are like the glue holding the atoms together.
- Ionic Bonds: Atoms trade electrons. These are weak bonds. For example, salt dissolves easily in water because these bonds break.
- Covalent Bonds: Atoms share electrons. These are very strong bonds.
- Metallic Bonds: Electrons flow freely between atoms. This allows metals to conduct electricity well.

Sometimes, the same "ingredients" can make different minerals depending on how they are bonded together. This is called a polymorph.

Graphite: Made of Carbon. The bonds are weak, so it is soft and used in pencils.
Diamond: Also made of Carbon, but the atoms are held together by strong covalent bonds, making it the hardest mineral.

Crystal Form (Habit): This is the natural shape a mineral grows in, like cubes or points, based on its internal pattern.
Color: This comes from how the mineral absorbs light.
- Some minerals always have the same color, like Gold or Sulfur.
- Many minerals change color because of tiny "impurities" (extra elements). For example, Quartz is normally clear, but Iron can turn it purple (Amethyst).
- The Hope Diamond: This famous gem is blue because it contains traces of the element Boron.

There are over 4,000 types of minerals, but most of the Earth's crust is made of just eight elements. We group minerals by their chemical parts:

Silicate Group: These are the most common. They are built from a "Silica Tetrahedron" shape (1 Silicon and 4 Oxygen atoms).
- Olivine: A simple structure found deep in the Earth.
- Pyroxene and Amphibole: These form chains of atoms.
- Micas: These form thin sheets that peel off easily.
- Quartz and Feldspar: These form complex 3D structures. Feldspar is the most common mineral in the entire crust.
Native Elements: Minerals made of just one element, like Gold ( $Au$ ) or Copper ( $Cu$ ).
Carbonates: Contain ( $CO_{3}^{2-}$ ), such as Calcite.
Halides: Known as "salts," such as Halite ( $NaCl$ ) and Fluorite.
Oxides: Contain Oxygen ( $O^{2-}$ ), such as Hematite or Corundum (which makes Rubies and Sapphires).
Sulfides and Sulfates: Contain Sulfur, such as Pyrite (Fool's Gold) or Gypsum.

From Magma: As melted rock (magma) cools down, minerals like those found in Granite start to crystallize.
From Liquids: Minerals can grow inside water-filled spaces.
- Geodes: Hollow rocks filled with crystals.
- Evaporation: When water dries up in the desert, it leaves behind salt pans.
From Gasses: Sulfur crystals can form directly from hot volcanic gasses.
Growth Secrets: Minerals grow by adding more modules to their structure. They can grow huge if they have enough space and the right temperature, like giant Topaz crystals that weigh over 100 lbs.

Paragenesis: This is when different minerals grow in the same place at the same time. This is how rocks are formed.
Inclusions: When one mineral grows faster, it might "swallow" a smaller mineral nearby.
Twins: Two crystals that grow together at specific angles because of their atomic pattern.

We use a massive amount of minerals every day. In the United States, each person requires about 39,469 lbs of new minerals every year.

Construction: Using stone, gravel, and cement.
Electronics: Copper for wires and Zinc to prevent rust.
Food/Agriculture: Salt for eating and Phosphate for plant fertilizer.
Smartphones: A phone is a "mineral goldmine." It uses:
- Indium Tin Oxide for the touch screen.
- Lithium for the battery.
- Silica and Aluminum for the glass screen, which is strengthened with Potassium ions.
- Rare Earth Elements to create the bright colors on the display.