What is a Mineral?  Naturally-formed solid substance with a crystal structure Pyromorphite

What do all minerals have in common? All: 1. Are formed by natural processes. 2. Are ORGANIC - NOT alive and NEVER were alive 3. Have a definite volume and shape 4. Are elements or compounds with a unique chemical makeup 1. Some are composed of just 1 element (Sulfur, Copper) 2. Most are composed of more than 1 element. 5. Are CRYSTALS – ordered structure of atoms 6. Solid

All Minerals Have Crystals -  A crystal is a regularly shaped solid formed by an organized pattern of atoms.  Crystal form, Fracture, and Cleavage are keys to mineral identification

Crystal Shapes  Cubic – Halite  Hexagonal – Quartz  Rhombohedral - Calcite

Crystal Formation - Magma  The rate of cooling of the magma determins the crystal size.  If it cools slooooooooow – larger crystals form  If it cools fast – smaller crystals form.  The atoms don’t have enough time to arrange themselves into large crystals

Crystal Formation - Evaporate  Minerals can form when elements are dissolved in a solution.  A solution is when one substance is dissolved in another substance.  Solvent – Does the dissolving  Solute – Is dissolved  When the liquid evaporates away, the elements remain behind and may arrange themselves in a crystalline structure (Mineral Deposit).  Known as an Evaporate or Precipitate  Ex - Gypsum

Watch “Crystals” by Brainpop…Crystals 1.What element are diamonds made from? 2. What do all crystals have in common?

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

Mineral Group CharacteristicsExamples Silicates – 1 Silica and 4 Oxygen in a Tetrahedron (Pyramid) Contain oxygen & silica Contain oxygen & silica The most abundant group of minerals The most abundant group of minerals Quartz, mica MICA Quartz

Mineral Group CharacteristicsExamples Non-Silicates Make up only 5% of the Earth’s crust Make up only 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 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)

MINERAL IDENTIFICATION HAVE OUT YOUR REFERENCE TABLES FOR THIS SECTION… AND FROM NOW ON… FOREVER…

PHYSICAL PROPERTIES Each mineral has specific properties that are a result of its chemical composition and its crystalline structure. There are SEVEN Physical Properties to determine the mineral type. LAST PAGE OF THE REFERENCE TABLE

PHYSICAL PROPERTIES OF MINERALS (CAN BE USED TO IDENTIFY THE MINERAL) #1 - Color Can be misleading Can vary with the type of impurities

COLOR CHECK -  Find the Common Colors Column  List two examples of minerals that are the same or similar colors…

# 2 - Luster Surface reflection – How light is reflected metallic = shiny like metal non-metallic = dull, non-shiny surface Pyrite has a metallic luster Calcite has a non-metallic luster PHYSICAL PROPERTIES OF MINERALS (CAN BE USED TO IDENTIFY THE MINERAL)

LUSTER CHECK -  Find the Luster Column  What are the 2 main types of Luster?  Identify the mineral that has a metallic luster, green black streak, and is brassy yellow…  Identify the mineral that has a non-metallic luster, is yellow to amber in color, and is easily melted…

PHYSICAL PROPERTIES OF MINERALS (CAN BE USED TO IDENTIFY THE MINERAL) # 3 - 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)

HARDNESS CHECK -  Find the Hardness Column  Using the Hardness Scale, list at least 2 examples of minerals that can be scratched by your fingernail.  List two that would scratch glass

PHYSICAL PROPERTIES OF MINERALS (CAN BE USED TO IDENTIFY THE MINERAL) # 4 - Streak The true 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 – IN GENERAL  Rub the mineral on a ceramic plate  The color of the streak indicates 3 things –  Metallic minerals usually have a dark streak  Non-metallic minerals usually have a light streak  Minerals harder than the streak plate will leave no streak. Why?

STREAK CHECK -  Find the Distinguishing Characteristics Column  List at least 2 examples of minerals that have a Black Streak.  What other characteristics could you use to identify minerals with the same color streak?

STREAK…CAN HELP IDENTIFY QUARTZ

FIND OUT MORE… “Electronic” Hardness Test

PHYSICAL PROPERTIES OF MINERALS (CAN BE USED TO IDENTIFY THE MINERAL) # 5 - 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?

PHYSICAL PROPERTIES OF MINERALS (CAN BE USED TO IDENTIFY THE MINERAL) # 6 – Crystal Shape  Crystal shape results from the pattern formed by the atoms of a mineral when it is forming. Most minerals have a characteristic geometric shape.  Table in text - 112

CRYSTAL SHAPE CHECK -  Find the Distinguishing Characteristics Column  Identify two minerals that have a cubic crystal structure.  Identify two minerals that have a rhombohedral crystal structure.

PHYSICAL PROPERTIES OF MINERALS (CAN BE USED TO IDENTIFY THE MINERAL) # 7 – Density  Each mineral has a characteristic density. Most minerals are between 2.0 and 3.0 g/cm 3  Specific Gravity – the ratio of the density of a mineral compared to the density of water. It is even more specific than density.

PHYSICAL PROPERTIES OF MINERALS (CAN BE USED TO IDENTIFY THE MINERAL) Other Properties  Magnetism - Attraction to magnets  Double Refraction - Bending of light  Acid Test - Reaction with hydrochloric acid, bubbles  Flourescence – Glows under Black Light  Smell & Taste

WATCH CLASSIFYING MINERALS CLIPCLASSIFYING MINERALS