• Mineral - a naturally occurring, inorganic solid that has a crystalline structure and a definite chemical composition
• For the Love of God
• A platinum cast of a skull from an actual person that lived between 1720 and 1810. He was a 35 year old man from Europe. The teeth are original. The skull is covered with 8,601 flawless diamonds. Cost £14 million to produce. Sold for £50 million in 2007.
• Naturally occurring: not man-made
• copper and zinc are both minerals; brass (a mixture of copper and zinc) is not a mineral
• Inorganic: not from anything that was at one time living
• gold is a mineral; coal is not a mineral
• Properties of Minerals
• 1) Color - many minerals have the same color (ex. gold and fool’s gold), so color is rarely enough information to identify a mineral
• 3) Luster - the way a mineral reflects light from its surface (ex. metallic, glassy, waxy, dull, earthy)
• 4) Density - (mass/volume) can be used to identify minerals
• (density of gold = 19.93 g/cc; fools gold = 5 g/cc)
• 5) Hardness - determined by a scratch test; a mineral can scratch any mineral softer than itself, but will be scratched by any mineral that is harder
• 7) Fracture and Cleavage - the way a mineral breaks apart
• fracture: irregular break; jagged, rough surface
4th Quarter Extra Credit Opportunity
• 20 points extra credit for a package of cookies
• Due: Thursday, March 24th
For each sample:
• #
• Name
• Picture (colored)
• At least two distinguishing properties
Example:
• #11
• sulfur
• Bright yellow
• Doesn’t scratch glass
• some rocks contain only one type of mineral; others are made of many different minerals combined together
• All minerals are rocks, but not all rocks are minerals.
• Igneous Rock - forms from cooling magma or lava
• Extrusive rock forms from lava that cools on the earth’s surface (ex. basalt, obsidian, pumice)
• Intrusive rock forms from magma that hardens beneath the Earth’s surface (ex. granite)
• Intrusive rock usually has larger grains than extrusive rock since it takes longer to cool (more time for crystals to grow)
• Sedimentary Rock - forms when sediment (small, solid pieces of material that come from rocks or living things) is pressed and cemented together
• 5 steps of sedimentary rock formation:
1) Weathering - rocks are broken down into sediments by physical and chemical processes
• 5 steps of sedimentary rock formation:
1) Weathering - rocks are broken down into sediments by physical and chemical processes
2) Erosion - sediments are carried from their source
• 5 steps of sedimentary rock formation:
1) Weathering - rocks are broken down into sediments by physical and chemical processes
2) Erosion - sediments are carried from their source
3) Deposition - sediments are deposited in a new area
• 5 steps of sedimentary rock formation:
1) Weathering - rocks are broken down into sediments by physical and chemical processes
2) Erosion - sediments are carried from their source
3) Deposition - sediments are deposited in a new area
4) Compaction - sediments are squeezed together under the pressure new layers of sediment above
• 5 steps of sedimentary rock formation:
1) Weathering - rocks are broken down into sediments by physical and chemical processes
2) Erosion - sediments are carried from their source
3) Deposition - sediments are deposited in a new area
4) Compaction - sediments are squeezed together under the pressure new layers of sediment above
5) Cementation - dissolved minerals crystallize and glue particles of sediment together
• 3 Types of Sedimentary Rocks
• Clastic Rock forms when rock fragments are squeezed together; the fragments can be very small or quite large
• ex. shale (from clay), sandstone, conglomerate (rounded rocks), and breccia (rock fragments with sharp edges)
• Organic Rock forms when the remains of plants and animals are deposited in thick layers
• ex. coal (from swamp plants) and limestone (from coral and shells)
• Chemical rock forms when minerals dissolved in solution crystallize (water evaporates or minerals precipitate out of solution)
• ex. rock salt, some limestone
• Metamorphic Rock - forms from an existing rock changed by extreme heat and pressure deep within Earth’s crust
• Foliated rocks have mineral grains arranged in parallel layers or bands
• ex. gneiss (from granite), slate (from shale)
• Nonfoliated rocks have mineral grains arranged randomly
• ex. quartzite (from sandstone), marble (from limestone)
• most fossils form when living things die and are buried by sediments
• the sediments slowly harden into rock and preserve the shape of the organism
• Types of Fossils –
• Mold and cast: a mold is a hollow area in the sediment in the shape of a dead organism; a cast is a solid copy of an organism’s shape, formed when minerals seep into the mold
• trace fossils - provide evidence of the activities of prehistoric organisms - ex. dinosaur footprint
• preserved remains - actual remains of an organism encased in tar, amber, or ice which prevent the organism from decaying fully (ex. mosquito, woolly mammoth)
• Law of Superposition - in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it
• Unconformity - a place where an old, eroded rock surface is in contact with a new rock layer; caused by erosion, faults, and folding
• Index fossils - if the same type of fossil is found in rock layers in different areas, those layers are the same age
• an index fossil must be widely distributed and represent a type of organism that existed only briefly
• 6 cookie maximum per person
• Do not insult any cookie (and therefore the person who brought it)
• Allergies? Check the package for ingredients
• Draw/write neatly; be detailed
• Clean up when you have finished
• Lab is due at the end of class
Hints for Classifying Cookies
• IgneousInter-grown CrystalsBubblesGlassy
• SedimentaryLayersFossilsFragments
• MetamorphicWarped/DistortedDenseFoliation/Bands