Lab+2+-+Rocks

**1. ROCKS**
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 * **Sedimentary**, **igneous**, and **metamorphic** rocks differ based on their processes of formation. Below are the differences among their processes:
 * //**IGNEOUS**//: formed through the cooling and solidification of magma or lava, and can either be below the surface (intrusive) or above the surface (extrusive).
 * //**METAMORPHIC**//: formed by the transition of an existing rock type, so a "change in form" through intense heat and pressure that causes profound physical and/or chemical change; can be below the surface, and an example that causes these types of rocks is plate tectonic movement.
 * **//SEDIMENTARY:// formed by the sedimentation of material on the Earth's surface and in bodies of water; it involves the settling and solidifying and precipitation of water from these materials, typically in layers. One example is glacial movement scraping and weathering the Earth's surface, building up layers of sediment and causing these sedimentary rock formations. **
 * **Three minerals of interest:**
 * **//GRAPHITE//:** graphite is a black mineral with a metallic, dull luster and a black streak when used on paper. It is quite soft, with a 1-2 hardness, and has somewhat of a greasy feel. Commercially, graphite is most well-known for its use in pencils, and because of this commercial use, is often referred to as "lead".
 * **//TALC:// talc is a mostly white, sometimes green, sometimes gray mineral that has a pearly, greasy luster and a white streak when used on paper. It is the softest mineral with a hardness of 1, and has a greasy feel. Commercially, talc is used in p ** aper making, plastic, paint and coatings, rubber, food, pharmaceuticals, cosmetics, and ceramics --- quite the extensive application for one mineral.
 * **//MAGNETITE:// magnetite is a iron-black mineral with a metallic luster and a black streak when used on paper. It is quite hard with a level 6 hardness, and is magnetic. Magnetite is most often used in coating industrial tube steam boilers, since it is quite durable. It is also used as a catalyst for various chemical processes. **

**2. SOIL COMPOSITION //(POTTER'S SOIL)//**
1. The basic idea behind separation is that sand drops to the bottom fast. Silt takes a little longer (30 min) to drop to the bottom. Clay takes 24 hours or more to come out of solution. Put three 50 ml tubes in a rack or cup. Put 15 ml of soil into the first tube to the 15 ml line. **Tap** the soil down to make sure it has no air pockets.

2. Use a pipette and add 1 ml of a little soapy water to the soil sample (it is a dispersent) and fill the tube to the 45 ml line with tap water. Cap and gently shake for 2 minutes making sure that the soil sample is well mixed in. REMOVE ORGANIC MATERIAL FROM THE TOP, be sure to dump into TRASH, not in the SINK. Then **add** water to fill to the 45 ml line if there is less than 45 ml.
 * PICTURE: [[image:tubes1.png]]**

3. Let the tube sit for **30 seconds**, open the cap and carefully pour the solution into the second tube. Be sure not to dump the solid contents into the second tube. Let this sit for **30 minutes**. a. read how much sand is left in the tube b. read how much liquid was poured over and subtract from 45 ml
 * PICTURE: [[image:tubes2.png]]**

4. Pour the solution off into the third tube and let this sit overnight.
 * PICTURE: [[image:tubes3.png]]**

5. Calculate how much of sand, silt and clay using this method: **b. method** **45 ml** minus fluid in tube 1 **(39ml)** = ml of sand **(6ml)** fluid in tube 1 **(39ml)** minus fluid in tube 2 **(36ml)** = silt **(3ml)** **15 ml** minus sand **(6ml) a**nd silt **(3ml)** = clay **(6ml)**


 * >  ||> **ml** ||> **percent** ||
 * > **sand** ||> 6ml ||> 40% ||
 * > **silt** ||> 3ml ||> 20% ||
 * > **clay** ||> 6ml ||> 40% ||

**MATH CALCULATIONS:** 6 ml (sand) / 15 ml (total) = .4 x 100 = 40% ....repeat for (silt) and (clay)


 * SOIL RESULT**: sandy clay loam

**3. FOSSILS**
> > >> **PICTURE: **
 * Casts are copies of fossilized plants or animals, while molds are hollow impressions of the fossil.
 * This is a picture of a cast, because it is a copy of a fossilized plant or animal, and because it is not hollow:


 * AMBER:** Amber is fossilized tree "resin", which is a hydrocarbon secretion that many plants emit. It emerges soft and sticky, which is why some amber has "stuff" inside, also because it often picks up tree residue like plant and animal material as it solidifies. Amber is appreciated for its natural color and organic beauty, often used in jewelry**,** and also sometimes found in perfumes.

Typically, artifacts from trees such as leaves or insects are preserved in amber, since amber is fossilized tree resin. Amber fossils differ from those in limestone in that Amber preserves the entire material inside, while limestone, a sedimentary formation, results in a cast or a mold copy or impression of the fossil, not the actual material. Some amber found dates back to around 20, 30 or even 40 million years, that has preserved some bacteria. Some amber has been found to contain DNA material in nucleotide sequence, but preservation of the dinosaur species is a myth. DNA is able to be preserved because of amber's ability to totally isolate the organic specimen from oxygen exposure.


 * Real v. Fake:** Amber, often, is imitated by "fake" amber, which is made by heating colored plastic, using copal (not "mature" amber), or other polymers. Real amber, however, is made from tree resin that has very gradually, very slowly hardened on through its own natural processes.


 * Testing:** In order to determine the difference between real and fake amber, a number of different tests can be administered -- some of these tests are more likely to be used than others, because they are less damaging to the "potential" amber. Of the less damaging ones, if one dissolves salt into water and drops the specimen in and it sinks, it is not amber. If it floats, it may be amber. If you are able to scratch the specimen with your fingernail, the specimen is not amber. If the specimen attracts velvet pieces through static electricity, it may be amber, and if it smells or tastes like plastic or chemicals, it is not amber. Another way is to determine if the organic material preserved inside is extinct or matches the location in which the amber was found. Be careful with this test, though, as animals can be "injected" into fake amber. Some of the more damaging tests (but also more telling) include heating a needle until it is red and if the needle enters easily or leaves a black mark, it is likely not amber. If the needle enters slowly and emits a turpentine-like smell, though, it could be amber. Another test includes dropping the specimen in alcohol, and if it dissolves the outer coating or if it becomes sticky, it is likely not amber.

If you administer several tests and the specimen passes some but not all, you could be dealing with copal, which is "young" amber, and only one-hundred to three-million years old. Copal is typically softer than actual amber (1.5 versus 2.5 on Moh's scale), has a lower melting point, and is generally brittle and sensitive to sunlight.


 * IF I STUMBLED UPON A CANDIDATE IN MILWAUKEE...** I would administer the smell and scratch test. Given I probably wouldn't be armed with many materials (like salt water or dating-methods for the organic material inside), these two tests would be easy on-site indicators. If the specimen easily scratched with my fingernail, I'd likely not purchase it. Also, I would rub the specimen on my shirt for a few minutes, and if it smelled like chemicals or plastic, I wouldn't purchase it. If it had a mild turpentine-like or pine-like odor, I would be more inclined to purchase it.
 * PICTURE: [[image:Amber.pendants.800pix.050203.jpg]]**