1 Rocks and Minerals GOLD! (before processing) Just what are they?
2 Mineral: A naturally created crystalline solid that was never alive: inorganic with distinct properties Opal! (Hydrous quartz)
3 Rocks : any naturally formed solid that is part of Earth, made up of one or more minerals. All minerals are rocks but not all rocks are minerals EX: Coal is not a mineral because it’s made of ancient plant material but it is a rock!
4 Where do rocks and minerals come from? Inside of and on the Earth They make up the solid surface of the Earth called the lithosphere
5 What are rocks and minerals used for? Write down 3 things you think contain or use minerals Pencils, jewelry, computers, tile, pipes, insulation, dishes, glass, makeup, toothpaste, roofing, tires, rubber, magnets, paint, cans, batteries, cars mouthwash, glue, medicine,, solder, fuel, fertilizer, explosives, photography, plastic, false teeth, catlitter, silverware, drywall, radioactive spill cleanup You get the idea? And oh yeah… 95% of all manmade things use minerals! we need minerals to live! Drywall or “sheetrock” is made of the fire resistant mineral: Gypsum
6 Mineral Composition Minerals are composed of elements and combinations of elements called compounds MOST of the Earth’s crust is only made up of a few elements.
7 DO NOW: Turn to page 11 in your reference tables What are the 2 most common elements in Earth’s Crust? Oxygen and Silicon Minerals formed from these elements are called silicates sound familiar? (non toxic. NOT with dopant cobalt)
8 Turn to page 16 in your reference tables What very common mineral has a composition of Silicon (Si) and Oxygen (0) QUARTZ! DO NOW: More varieties of QUARTZ!
9 There are ~ 4 thousand minerals! What can we do to separate and classify each mineral? What characteristics can we use??? Time to Classify…
10 1.Using observations come up with 10 ways to classify the samples given to you 2.Break up into groups 3.Record your results on one page to be turned in with your names Classification Assignment
11 Properties of Minerals Common ways to classify minerals. 1.Hardness: Found by scratching minerals of unknown hardness with minerals of KNOWN hardness (1812 Fredrich. Mohs)
12 Softest 1. Talc 2. Gypsum 3. Calcite 4. Fluorite 5. Apatite 6. Feldspar 7. Quartz 8. Topaz 9. Corundum 10. Diamond Hardest Moh’s Scale of Hardness Many of the harder ones are used as gemstones! (they resist scratching) An Uncut Diamond Powdered diamond
13 Properties of Minerals 2. Color: Light Colors (tan pink white) often contain aluminum and silica. Dark Colors often contain iron, magnesium or calcium
14 Color is not a good ID characteristic to use alone WHY NOT? Many different minerals can have the same color!
15 Properties of Minerals 3. Streak: Color of a mineral when powdered on a streak plate While a minerals color may change the streak color is unique (and usually stays the same!!)
16 Properties of Minerals 4. Cleavage or Fracture: Property of a mineral to split apart into neat smooth planes (cleavage) or to break into uneven pieces like glass (fracture) cleavage fracture Cleavage or fracture?
17 The main reason minerals have different properties is due to their different atomic structures SALT NaCl crystals Carbon in sheets… Carbon bonded equally in every direction 8 Allotropes of carbon
18 This minerals’ atoms are bonded in loose sheets, So the mineral itself has Sheet (Basal) Cleavage Biotite mica
19 Properties of Minerals 5. Crystal Shape: If a crystal has grown large enough, you can see different crystal shapes based on what it’s atomic structure is Hexagonal Quartz
22 Crystal Structure Different minerals exhibit different crystal shapes It depends on what elements are present in the magma they form from. Because some elements are more likely to form bonds than others (chem. 101)
23 Crystal Structure If given enough time to grow the crystal structure will become visible to the naked eye Often a crystal will run out of room or material or cool too fast and remain somewhat small Evaporite Gypsum in Mexico Crystal Cave
24 Crystal Structure of Silicates Silicon Tetrahedron The basic building block of silicates. How many sides? 24
25 Single Chain Silicates The atomic structure is long chains, so given time the mineral’s form appears as long chains or “fibers” 25
26 Splinter/Fibrous fracture So due to it’s atomic structure this mineral’s physical form has
27 Properties of Minerals 6. Luster: Describes how a mineral reflects (or doesn’t reflect) light EX: Metallic, Non-metallic Chatoyancy Shiny
28 Properties of Minerals 7. Other: Radioactivity Taste (like Halite:salt!) Fluorescence (glows in Ultraviolet light) Smell like many sulfur containing minerals!
29 3 Methods of Mineral Formation 1) From cooling and solidifying magma (lava) 2) As a precipitate from a liquid; (like when sea water evaporates leaving salt!) 3) From a solid TO another solid. This takes a long time!