Class Work Watch the video clip and answer the following questions: 1. How did we know about the earth’s interior for so long? 2. What did scientists begin to use to understand the center of the earth? 3. What do seismic waves measure? 4. What is the inner core made up of? 5. What does the inner core generate for planet Earth?

What is a Mineral? Naturally-formed solid substance with a specific chemical & crystal structure Pyromorphite

What do all minerals have in common? All: 1.Are inorganic. Are NOT alive and NEVER were alive 2.Are formed by natural processes. 3.A crystalline solid that has a definite volume and shape. Are made up of particles that are arranged in a pattern that is repeated over and over (called a CRYSTAL) 4.Are elements or compounds with a unique chemical makeup

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

Mineral Group CharacteristicsExamples Silicates Contain oxygen & silica Contain oxygen & silica The most abundant group of minerals The most abundant group of minerals Quartz (SiO2), mica MICA Quartz

Mineral Group CharacteristicsExamples Non-Silicates Make up only 4-5% of the Earth’s crust Make up only 4-5% of the Earth’s crust Include some of the most important minerals Include some of the most important minerals iron, copper, gold, silver, diamonds, rubies Silver Gold Ruby Iron Copper Diamond

Mineral Group CharacteristicsExamples Carbonates Carbon & oxygen and a positive ion, such as calcium Carbon & oxygen and a positive ion, such as calcium Calcite (CaCO 3 ) Calcite with Duftite inclusions

Mineral Group CharacteristicsExamples Oxides  Metallic ion and oxygen Hematite (Fe 2 )O 3

Mineral Group CharacteristicsExamples Sulfides  Sulfur and a metallic ion Galena (PbS)

Mineral Group CharacteristicsExamples Halides  Chlorine & fluorine combined with sodium, potassium or calcium Halite (NaCl) Fluorite (CaF2)

Mineral Group CharacteristicsExamples Sulfates  Metallic ion, Sulfur & oxygen Barite (BaSO 4 ) Barite on Calcite BaSo4 / CaCO3 Barite BaSo4

Mineral Group CharacteristicsExamples Native Elements  Single elements Gold (Au), Diamond (C), Silver (Ag)

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

How do minerals form? Evaporites 2) form when elements & compounds remain behind when water evaporates. Dissolved in liquids: usually water. (Think of rock candy.)

Physical Properties of Minerals (can be used to identify the mineral) Color Can be misleading Can vary with the type of impurities

Physical Properties of Minerals (can be used to identify the mineral) Luster Surface reflection metallic = shiny like metal non-metallic = dull, earthy, virteous, non- shiny surface Pyrite has a metallic luster Calcite has a non-metallic luster

Luster Characteristics Adamantine - very gemmy crystals Dull - just a non-reflective surface of any kind Earthy - the look of dirt or dried mud Fibrous - the look of fibers Greasy - the look of grease Gumdrop - the look a sucked on hard candy Metallic - the look of metals Pearly - the look of a pearl Pitchy - the look of tar Resinous - the look of resins such as dried glue or chewing gum Silky - the look of silk, similar to fibrous but more compact Submetallic - a poor metallic luster, opaque but reflecting little light Vitreous - the most common luster, it simply means the look of glass Waxy - the look of wax

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

Streak…can help identify quartz

Physical Properties of Minerals (can be used to identify the mineral) Hardness How easily a mineral scratches materials Mohs 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)

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

Cleavage or Fracture?

Minerals Minerals: More Characteristics Taste (ex. Halite) Taste (ex. Halite) Fluorescence (ex. Fluorite) Fluorescence (ex. Fluorite) Phosphorescence (ex. Willemite) Phosphorescence (ex. Willemite) Radioactivity (ex. Uraninite) Radioactivity (ex. Uraninite) Double refraction (ex. Calcite) Double refraction (ex. Calcite) Magnetism (ex. Magnetite) Magnetism (ex. Magnetite) Reactivity to acids (ex. Calcite) Reactivity to acids (ex. Calcite)

Physical Properties of Minerals (can be used to identify the mineral) Other Properties – Specific gravity (*excellent clue to mineral’s identity) – Attraction to magnets – Bending of light – Reaction with hydrochloric acid – Smell & taste

Giant Crystal Caves DLE

Watch Identifying Minerals ClipIdentifying Minerals

Answer the following questions in your notebook…  How many minerals have scientists discovered?  Of them only _______ are the most common minerals.  What is the composition of the rock Basalt? (This makes up the dense oceanic crust.)