1. Bellringer #65: Why
are minerals like
gems so valuable?

2. Minerals

3. What is a Mineral?
Naturally-formed, inorganic solid substance with a definite crystalline structure
Pyromorphite

4. What do all minerals have in common?
Are formed by natural processes.
Are NOT alive and NEVER were alive
Have a definite volume and shape
Are elements or compounds with a unique chemical makeup
Are made up of particles that are arranged in a pattern that is repeated over and over (called a CRYSTAL)

5. Watch “Crystals” by Brainpop…
.What element are diamonds made from?
. What do all crystals have in common?

6. Elements, Atoms, and Compounds
Elements – pure substances that cannot be broken down into simpler substances by ordinary chemical means. All minerals contain one or more of the 92 naturally occurring elements.
Example: oxygen, carbon, sulfur, hydrogen
Atoms – the smallest part of an element that has all the properties of that element. Minerals are made up of atoms of one or more elements.
Compounds – a substance made of two or more elements that have been chemically joined.
Example: water (H2O), salt (NaCl)

7. Groups of Minerals
Minerals are grouped by the elements they are made of.
Beryl (Emerald)
Calcite
Amethyst

8. Mineral Group Characteristics Examples Silicates
Contain oxygen & silicon
The most abundant group of minerals
Make up more than 90% of the Earth’s crust.
Quartz, mica, feldspar
MICA
Quartz

9. iron, copper, gold, silver, diamonds, rubies
Mineral Group
Characteristics
Examples
Non-Silicates
(native elements, carbonates, halides, oxides, sulfates, and sulfides)
Do NOT contain silicon and oxygen
Make up only 5% of the Earth’s crust
Include some of the most important minerals
iron, copper, gold, silver, diamonds, rubies
Silver
Copper
Diamond
Gold
Iron
Ruby

10. Mineral Group Characteristics Examples Carbonates Calcite (CaCO3)
Carbon & oxygen and a positive ion, such as calcium
Used in cement, building stones, and fireworks.
Calcite (CaCO3)
Calcite with Duftite inclusions

11. Mineral Group Characteristics Examples Oxides Hematite (Fe2)O3
Metallic ion (aluminum/iron, etc.) and oxygen
Used to make abrasives, aircraft parts, and paint.
Hematite (Fe2)O3

12. Mineral Group Characteristics Examples Sulfides Galena (PbS)
Sulfur and a metallic ion such as lead, iron, or nickel
Used to make batteries, medicines, and electronic parts
Galena (PbS)

13. Mineral Group Characteristics Examples Sulfates Barite (BaSO4)
Metallic ion, Sulfur & oxygen
Used in cosmetics, toothpaste cement, and paint.
Barite (BaSO4)
Barite BaSo4
Barite on Calcite BaSo4 / CaCO3

14. Mineral Group
Characteristics
Examples
Native Elements
Single elements
Gold (Au), Diamond (C), Silver (Ag)

15. How do minerals form?
1) Cooling of magma (hot, liquid rock and minerals inside the earth (from the mantle))
Fast Cooling = No Crystals (mineraloids)
Medium Cooling = small crystals
Slow Cooling = large crystals

16. How do minerals form?
2) Elements dissolved in liquids (usually water)

17. Physical Properties of Minerals (can be used to identify the mineral)
Color
Can be misleading
Not the best way to identify a mineral
Can vary with the type of impurities

18. Physical Properties of Minerals (can be used to identify the mineral)
Luster
Surface reflection
How shiny or dull an object is
metallic = shiny like metal
non-metallic = dull, non-shiny surface
Pyrite has a metallic luster
Calcite has a non-metallic luster

19. Physical Properties of Minerals (can be used to identify the mineral)
Streak
The color of the mineral in powdered form
The color of the streak can be different than the mineral
Minerals must be softer than the streak plate

20. Streak…can help identify quartz
BUT...

21. Physical Properties of Minerals (can be used to identify the mineral)
Hardness
How easily a mineral scratches materials
Moh’s Hardness Scale
Scale from 1 (softest) to 10 (hardest)
Test by seeing if the mineral can scratch different objects (like human fingernail, copper, penny, glass, steel file)

22. Find out more… “Electronic” Hardness Test

23. Physical Properties of Minerals (can be used to identify the mineral)
Cleavage & Fracture
The way the mineral breaks
Cleavage—minerals break along smooth, flat surfaces and every fragment has the same general shape
Fracture—minerals that break at random with rough or jagged edges

25. Cleavage or Fracture? 1. 4. 3. 2.

26. Physical Properties of Minerals (can be used to identify the mineral)
Other Properties
Specific gravity (*excellent clue to mineral’s identity) – the ratio of an object’s density to the density of water
Attraction to magnets (magnetism)
Fluorescence (glow under ultraviolet light)
Bending of light (double images)
Reaction with hydrochloric acid (chemical reaction)
Smell & taste

27. Watch Brainpop—“Mineral Identification”
. If a mineral can scratch your fingernail, the mineral is _______________ than your fingernail.
2. What is luster?