Minerals What is a mineral? How do minerals form? How can minerals be identified?

Key Terms To be a Mineral, Something Must. . . Crystal form Lattice Density Luster Inorganic Streak Chemical formula Hardness Cleavage Fracture Minerals are the building blocks of rocks, and therefore of the earth itself. To be a Mineral, Something Must. . .

Naturally Occurring Naturally Occurring Solid Inorganic Orderly Crystal Grid or Lattice Have A Definite Chemical Formula Naturally occurring means the substance cannot be human-created. For example: Ice found in snowflakes or glaciers are minerals Ice in your kitchen freezer is not made naturally and is not a mineral. Liquids and gases can become minerals only if they change to a solid.

Solid Solid Always solid state of matter Definite volume and shape Naturally Occurring Solid Inorganic Orderly Crystal Grid or Lattice Have A Definite Chemical Formula Always solid state of matter Definite volume and shape Particles are packed together very tightly Cannot move compared to a liquid or gas

Inorganic or Organic Inorganic Naturally Occurring Solid Inorganic Orderly Crystal Grid or Lattice Have A Definite Chemical Formula Inorganic means carbon that comes from living things is not present. Minerals are not formed from organic materials such as plant or animal remains.

Crystalline Grid or Lattice Naturally Occurring Solid Inorganic Orderly Crystal Grid or Lattice Have A Definite Chemical Formula The atoms in minerals are arranged in an orderly pattern that repeats itself throughout the substance This structure, because of the chemical formula, is called crystalline.

Crystalline Grid a/k/a Lattice Naturally Occurring Solid Inorganic Orderly Crystal Grid or Lattice Have A Definite Chemical Formula Notice the difference in a mineral’s orderly and repeating structure when compared to the randomly arranged atom of a non- mineral.

Definite Chemical Formula Naturally Occurring Solid Inorganic Orderly Crystal Grid or Lattice Have A Definite Chemical Formula When the atoms are the same in number and type, the chemical formula is known. Regardless of the state of matter (solid, liquid, or gas) a specific mineral will have the same formula throughout. Common formulas are: Water: H2O Diamonds: C

Minerals Form in Four Ways Crystallization from magma or other liquids Precipitation from solution Heat and Pressure Hydrothermal solutions Crystalline structure can occur when melted rock material cools into a solid. Water will crystalize when a lake freezes over and ice covers its surface.

Minerals Form in Four Ways Crystallization from magma or other liquids Precipitation from solution Heat and Pressure Hydrothermal solutions Minerals dissolved in water (solution) can precipitate (fall to the bottom) when the concentration is high enough.

Minerals Form in Four Ways Crystallization from magma or other liquids Precipitation from solution Heat and Pressure Hydrothermal solutions Extreme heat and pressure in the Earth can cause minerals to change form – without actually melting them. Because of this, different chemical bonds can form that changes the crystal lattice.

Minerals Form in Four Ways Crystallization from magma or other liquids Precipitation from solution Heat and Pressure Hydrothermal solutions Beneath the Earth’s surface water is super-heated so that it remains liquid instead of becoming steam. When this super-heated chemical solution contacts rocks and other minerals a new mineral is formed as a result other the chemical reaction.

Mineral Identification Color – Natural appearance Streak – Powdered form Luster – Metallic or Non- Metallic

Mineral Identification Hardness – Moh’s Hardness Scale Crystal System – Six structures

Other Methods of Mineral Identification Density – Mass per unit of volume (D = Mass/Volume) Cleavage and Fracture – how does it break? Special Properties – optical or electrical properties