Transcript Slide 1
By: Megan Tietz What is a Mineral? A mineral is an inorganic naturallyoccurring crystalline solid. It has specific physical properties and a definite chemical composition. http://www.sdnhm.org/kids/minerals/faq.html#mineral What is a Rock? A rock is usually composed of 2 or more minerals in some physical combination, although some rocks are composed of only one mineral. Is a Rock a Mineral? No. Although a rock is also inorganic and occurs naturally, it is not a crystalline solid. It is a consolidated material composed of grains of one or more minerals . http://www.sdnhm.org/kids/minerals/faq.html#mineral How are Rocks Formed There are three types of ways rocks are formed… Sedimentary Rocks Igneous Rocks Metamorphic Rocks Sedimentary Rocks When rocky fragments and sediments are deposited together by wind, water or ice, they gradually (over thousands or more years) cement together into new rocks, called sedimentary rocks. Limestone and sandstone are common sedimentary rocks. You can often find fossils embedded in these rocks—they were deposited together with the sediments! http://www.childrensmuseum.org/geomysteries/faqs.html Limestone Shale Conglomerate Gypsum Sandstone http://sln.fi.edu/fellows/payton/rocks/expert/gneiss.htm Igneous Rocks When molten rock called magma rises up from the earth's mantle deep underground, it forms igneous rocks. Some igneous rocks erupt from volcanoes as lava or pumice. Others, like granite, form in underground magma chambers. http://www.childrensmuseum.org/geomysteries/faqs.html Granite Scoria Pumice Obsidian http://sln.fi.edu/fellows/payton/rocks/expert/gneiss.htm Metamorphic Rocks Sometimes sedimentary and igneous rocks are changed dramatically by forces inside the Earth. Extreme heat or pressure underground can bake, squeeze, or fold rocks into something new. Then they are called metamorphic rocks—metamorphic is Greek for "change of form.“ http://www.childrensmuseum.org/geomysteries/faqs.html Schist Gneiss http://sln.fi.edu/fellows/payton/rocks/expert/gneiss.htm www.cotf.edu/ete/modules/msese/earthsysflr/rock.html Does the Rock Cycle Ever Stop? No, the rock cycle never stops. Rocks keep breaking down and into pieces and keep changing into other types of rocks. It’s just one big cycle that keeps going and going… Rocks and Heat All rock can be heated. But where does the heat come from? Inside Earth there is heat from pressure (push your hands together very hard and feel the heat). There is heat from friction (rub your hands together and feel the heat). There is also heat from radioactive decay (the process that gives us nuclear power plants that make electricity). So, what does the heat do to the rock? It bakes the rock. http://www.cotf.edu/ete/modules/msese/earthsysflr/rock.html Properties of a Mineral You can tell the differences between minerals by looking for certain properties. Because each mineral is unique both chemically and structurally, each has its own set of physical, optical, and structural properties which aid in its identification. http://rockhoundingar.com/pebblepups/basics.html What are the Physical Properties? Specific Gravity Streak Hardness Light Dependent properties – Color – Luster – Diaphany Moh’s Rock Hardness Scale 1 2 3 4 5 6 7 8 9 10 Talc Gypsum Calcite Fluorite Apatite Orthocla se Quartz Topaz Corundum Diamond http://www.childrensmuseum.org/geomysteries/faqs.html When can you start collecting? The best thing about starting a geology collection is that you get to collect a little bit of everything. After a while you'll discover what you're most interested in, and be able to concentrate on a certain area. For example, you may focus on collecting fossil shark teeth, or on fossils of the Cretaceous period, or even on minerals that are the color blue! You can look for rocks and minerals anywhere, even when you on family vacations or out at the park. Just make sure your in an area that it’s ok to take them.