Rocks & Minerals

THE DIFFERENCE BETWEEN ROCKS & MINERALS It is not easy to tell the difference between rocks & minerals because there are so many kinds of them. There are 3000 known minerals on Earth! There are 3 main rock types but hundreds of sub-categories

It takes years of study to be able to accurately identify a mystery rock and even then geologists want to know where the specimen came from. First the basics: 2. A rock is made up of 2 or more minerals. 1. All rocks are made of minerals. 3. You need minerals to make rocks, but you don't need rocks to make minerals.

Think of a chocolate chip cookie as a rock. The cookie is made of flour, butter, sugar & chocolate The cookie is like a rock and the flour, butter, sugar & chocolate are like minerals. Leave MY cookies alone! In your notes finish this sentence: A chocolate chip cookie is like a rock...

The three types include: Rocks are divided into:3 Types They are classified by: How they were formed 1.Igneous 2. Sedimentary 3. Metamorphic

Rock Words: There are many common names for rocks and the usually give you an idea of how big the rock is. Here are a few: - huge, giant hunk of rock that is still attached to the earth's crust, doesn't move, tall - large, taller than a person - large, you could get your arms around it or a bit smaller but it is usually jagged, broken off a bigger piece of rock - round rocks that are along the edge & at the bottom of fast-flowing rivers - medium, you could hold it in two hands - small, you can hold it with two fingers, could get stuck in your shoe, usually rounded - made up of tiny pieces of rock, grains of sand - tiny, like a grain of rice or smaller, often found on a beach mountain boulder rock river rock stone pebble sand grain

The rocks you see around you - the mountains, canyons & riverbeds, are all made of minerals

So... What is a MINERAL? 4. A mineral is composed of the same substance throughout - if you were to cut a mineral sample, it would look the same inside and out 1. A solid NOT a gas or liquid 2. Naturally forming NOT man-made 3. Inorganic NOT living

90% of the Earth’s crust are SILICATE minerals

Characteristics used in the identification & study of minerals 1.Color – this varies depending on the chemicals present and is the least informative (reliable) in identifying a mineral because it can change or the same mineral can come in a variety of colors Both of these samples are the mineral fluorite.

2. Luster – What the surface looks like in the light – is it shiny or dull?

3. Hardness – What it can scratch & What scratches it Scratching tools: fingernail (2.2) copper penny (3.5) pocket knife or common nail (5.2) piece of glass (5.5) steel file or concrete nail (7.5) piece of corundum (9)

5. Fracture - is when a mineral breaks, but the surface is not regular, does not show cleavage. 4. Cleavage - is when a mineral breaks with smooth flat surfaces.

6. Density / Specific Gravity – how heavy it feels, heft

7. Tenacity - is how tough a mineral is, how easily a mineral will break, split, crumble or change shape. 8. Transparency - The ability to transmit light. Transparent Translucent Opaque

9. Streak – The color of the mineral in powdered form. The mineral is rubbed against a piece of unglazed porcelain called a streak plate.