Minerals… The BIG Idea! Minerals are all around us. A mineral is identified by its properties. Minerals are valuable resources.
How many different types of minerals are there? Thousands! Most are rare-only about 100 occurring in abundance. Of those 100 minerals, 15-30 make up the common rock-forming minerals and some of the remainder have some economic value. Galena is a mineral used to make paints
Minerals are everywhere and used daily… Pots and pans are made from metal – stainless steel, cast iron, copper or aluminum. All of these come from minerals. Common salt is made from a mineral known as Halite.
Did you know… Pencils contain a mineral called graphite. Toothpaste is made with a mineral Fluorite.
Give me light… When you switch on a light, electricity flows through copper wires and into a filament made of tungsten (which comes from a mineral called wolframite). The filament glows and shines through a light bulb of glass (made from quartz)….Mineral teamwork!
What are the five characteristics of Minerals? Forms in nature (by processes that do not involve living things). Is a solid. Has a definite chemical makeup. Has a 3-D crystal structure. They are inorganic
Minerals are solids… They are solids, not liquids or gases, such as water and air. Solids have a definite volume and a rigid shape. Oxygen occurs naturally… Is it a mineral? NO…it is a gas An ice cube is a solid form of water and may occur naturally…Is it a mineral? NO! (no definite 3-D shape.)
Minerals have a definite chemical make up … Each mineral has a definite chemical composition - each one is made of a particular mix of chemical elements. A mineral’s atoms are arranged in a definite pattern repeated over and over again. Most minerals are compounds (more than one element) EXCEPT for two special minerals: GOLD and COPPER they are made of just one element.
Minerals have a geometric or crystal structure… Each mineral has its own type of crystal structure. A solid in which the atoms are arranged in an orderly, repeating three dimensional pattern. Crystal groups are named by their shapes.
Crystal Patterns There are six major crystal systems. Crystals can form from magma… When magma cools rapidly, the crystals that form will be small. When magma cools slowly, the crystals that form are generally large.
Minerals form in nature… Minerals must occur naturally. This means they are not made by humans. Substances such as steel and cement would not be considered minerals. For example… Talc is formed deep in the Earth. …Talc is used in cosmetics and baby powders. This is what the mineral talc looks like!
Minerals are Inorganic Living things can produce minerals within them like human beings produce calcite in their teeth and bones. Seashells are high in calcite.
Minerals are grouped and classified based on their chemical makeup 1) Silicates (silicon + oxygen)… most common. The silicates make up 90% of the rocks in Earth’s crust. Quartz and Mica are examples. 2) Carbonates (carbon + oxygen)…second most common. Calcite is an example. Quartz Mica Calcite
How are minerals identified? 1. Color 2. Streak 3. Luster 4. Cleavage 5. Fracture 6. Hardness
Mineral Properties...Color/Appearance Color and appearance are two obvious clues that can be used to identify minerals. Color is one of the least reliable properties because a mineral may have a variety of colors.
Mineral properties...Streak When a mineral is rubbed across a piece of tile, a streak or powder is left behind. Streak is the color of a mineral when it is in a powdered form.
The way a mineral reflects light is known as luster. Luster can be metallic (like metal) nonmetallic (dull, pearly, silky, and glassy). Mineral properties...Luster
Mineral properties...Cleavage Minerals that break along smooth, flat surfaces. The bonds of the crystal structure are weaker in the directions in which the mineral breaks. Calcite has cleavage.
Mineral properties...Fracture Minerals that break with uneven, rough, or jagged. When a mineral fractures, the bonds that join the atoms are equal in strength. Sulfur
Mineral properties...Hardness A mineral’s hardness is its resistance to being scratched. Harder minerals have stronger bonds.
Other Properties… Light forms two separate rays when it passes through calcite, causing you to see a double image. Some minerals… Have a magnetic quality, such as magnetite. React with a weak acid (bubble/fizz). Glow with a black light: fluoresce
Are minerals and rocks the same? No! Rocks share two characteristics with minerals… They are solids Form naturally Rocks contain one or more minerals within them.
Can you remember? Minerals that contain silicon and oxygen are __________. A. magma B. opals C. silicates D. solutions The answer is C. Silicates contain silicon and oxygen and usually one or more other elements.
Can you remember? Which of these is a characteristic of minerals? A. solid B. formed by life processes C. indefinite chemical composition D. organic substances The answer is A. Minerals are solids. Only a solid can be a mineral, but not all solids are minerals.
Minerals that break easily along smooth, flat surfaces have __________. Can you remember? A. cleavage B. fracture C. luster D. Streak The answer is A. Cleavage is determined partly by the arrangement of the mineral’s atoms. Minerals that break with uneven surfaces have fracture.
Minerals that break into irregular, jagged pieces, have __________. Can you remember? A. cleavage B. fracture C. luster D. streak The answer is B. Minerals that break with uneven surfaces have fracture.