What is a Mineral?
• Mineral: a naturally formed, inorganic solid that
has a definite crystalline structure
• How do I know?
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Q1: Is it non-living?
Q2: Is it a solid?
Q3: Does it have a crystalline structure?
Q4: Is it formed in nature?
If yes to all, then it’s a mineral!
How Do Minerals Form?
• 3 Ways:
–Cooling of melted rock (magma)
–Evaporation of liquid (like salt)
–Saturated solutions (dissolved
elements in a liquid)
Mineral Structure
• Minerals may either be elements or
compounds
• Elements: pure substances that can’t be
broken down into simpler substances and
keep their identity
• Compounds: a substance made of atoms of
two or more elements bonded together.
Groups of Minerals
• Minerals are divided into two groups based on their
composition (ingredients)
– Silicate Minerals: contain Silicon, Oxygen and 1 or more
metals
• examples: quartz, feldspar, mica
– Non-Silicate Minerals: don’t contain Silicon & Oxygen
• Native Elements – one pure element (Gold)
• Carbonates –contain Carbon and Oxygen
• Halides – (salts) formed when Fluorine, Chlorine, Iodine , or
Bromine bond with Sodium, Potassium, or Calcium
• Oxides – elements that bond with Oxygen
• Sulfates – contain Sulfur and Oxygen (SO4)
• Sulfides – elements bonded with Sulfur such as Lead, Iron or Nickel
Identifying Minerals
• You can identify minerals by using their physical
properties:
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Color
Luster
Streak
Cleavage
Fracture
Hardness
Density
Some others have special properties (taste,
magnetism, fluorescence, etc.)
Mineral Color
• Minerals display a wide variety of colors, and
often the same mineral can be found in many
different colors.
• Because of this, color is usually not the best
way to identify a mineral.
Mineral Luster
• The way a mineral reflects light is called luster.
• There are three types of mineral luster:
• Metallic
• Submetallic (similar to metallic but slightly less
reflective)
• Nonmetallic
Mineral Streak
• The color of a mineral in powdered
form is called the mineral’s streak.
• Streak can be found by running the
mineral against a piece of unglazed
porcelain called a streak plate.
• The color of a mineral’s streak is
not always the same as the color of
the mineral sample.
Mineral Breaking: Cleavage & Fracture
• Different types of minerals
break in different ways.
• Cleavage is the tendency
of some minerals to break
along smooth, flat surfaces.
• Fracture is the tendency of
some minerals to break
unevenly along curved or
irregular surfaces.
Mineral Hardness
• A mineral’s resistance to
being scratched is called
hardness.
• To determine the hardness
of minerals, scientists use
Mohs hardness scale.
Mohs Hardness Scale
Mineral Density
• Density is the measure of how much matter is
in a given amount of space. Density is a ratio
of an object’s mass to its volume.
• Different minerals
have different densities.
Special Properties of Minerals