Presentation on theme: "What is a Mineral? A mineral is a naturally formed, inorganic solid that has a definite crystalline structure and chemical composition."— Presentation transcript:
What is a Mineral? A mineral is a naturally formed, inorganic solid that has a definite crystalline structure and chemical composition.
What is a Mineral? 1. naturally formed 2. Inorganic 3. solid. 4. Crystalline structure 5. Definite chemical composition
(5) Characteristics of Minerals Naturally Formed- must form naturally, not man- made Ex._______________Non-ex.___________ Fossils*electronics Apples, fruits, vegetables*paper Trees* clothes Water rocks Natural: you can find it in NATURE
(5) Characteristics of Minerals Inorganic- cannot arise from materials that were once part of a living thing Ex.______________ Non-Ex._________________ Most rocks*decaying leaves Water*tree Clouds*fossils
A Mineral is Inorganic it's never alive, it never will be
organic (fossils are formed from the remains of once living organisms).
(5) Characteristics of Minerals Solid- always solid, not a liquid or gas. It has a definite volume and a definite shape
(5) Characteristics of Minerals Crystalline Structure- particles must line up in a pattern that repeats over and over again
Crystals Crystals are solid, geometric forms produced by a repeating pattern of atoms or molecules that are present throughout the mineral. A crystal’s shape is determined by the arrangement of the atoms or molecules within the crystal. All minerals can be grouped into crystal classes according to the kinds of crystals they form.
Crystals have a definite pattern….. This crystal prism has a pattern or design that it creates as light passes through it.
(5) Characteristics of Minerals Definite Chemical Composition- always contains certain elements in definite proportions. NaCl (salt)
(5) Characteristics of Minerals Solid- always solid, not a liquid or gas. It has a definite volume and a definite shape Naturally Formed- must form naturally, not man- made Inorganic- cannot arise from materials that were once part of a living thing Crystalline Structure- particles must line up in a pattern that repeats over and over again Definite Chemical Composition- always contains certain elements in definite proportions. NaCl (salt)
A mineral is a naturally formed, inorganic solid that has a crystal structure and a definite chemical composition. Each mineral has its own set of specific physical properties that can be used to identify it (hardness, color, streak, luster, density, crystal system, cleavage and fracture). An element is a substance composed of a single kind of atom. A compound is two or more elements combined so that the elements no longer have their original distinct properties.
Identifying Minerals Hardness- Moh’s scale ranks ten minerals from softest to hardest. Resistance to scratch Color- Because of factors, such as impurities, used only to identify a few minerals Streak- the color of a mineral in its powdered form Luster- how a mineral reflects light from its surface Density- the ratio of the mass to the volume of a substance Crystal Systems- six groups of structures based on the number and angle of the crystal faces Cleavage – splitting along smooth, flat surface Fracture- breaking apart along curved or irregular surfaces
Identifying Minerals Properties: Color, Luster, Streak, Density, Hardness, Cleavage, Fracture, and Special Properties
Color The same mineral can come in a variety of colors – Ex. quartz Impurities & other factors can change mineral appearance Color is not the best way to identify minerals
Luster Describes how a surface reflects light – Ex. shiny/dull Metallic- minerals containing metals are often shiny
Luster Examples of Nonmetallic – Vitreous- glassy, brilliant – Silky-fibrous – Resinous-plastic – Waxy- greasy, oily – Pearly- creamy – Earthy- rough, dull Nonmetallic- not as shiny
Streak Color of mineral in powder form Observed by rubbing a mineral against a piece of unglazed porcelain called a streak plate Streak doesn’t vary like color & is often different than a mineral’s color More reliable than color
Mohs Hardness Scale Talc1Softest known mineral Gypsum2fingernail can scratch it Calcite3scratched by copper penny Fluorite4easily scratched by steel knife Apatite5can be scratched by steel knife Orthoclase6can scratch window glass Quartz7can scratch steel Topaz8can scratch quartz Corundum9can scratch topaz Diamond10hardest known mineral
Density mass (how heavy it is) per unit volume (how much space it takes up) D= M/V Density remains same regardless of sample size Mass determined using balance Volume determined using water displacement method. Ex: gold is heavier than pyrite (fools gold)
Special Properties Some properties are particular to only a few types of minerals: Fluorescence – glow under ultraviolet light Chemical Reactions – reacts to an acid Magnetism – natural magnets that attract iron. Taste – ex. Halite has a salty taste Optical Properties – some can cause a double image Radioactivity – minerals that contain radium or uranium