Rocks and Minerals

General
You and your teammate basically identify rocks and minerals and answer questions about them. This competition is in a station format. Also your partner and you are allowed 1 3-ringed binder [any size (try for one thats not too big and complex or one thats too small)] and ONE book

Speed is the key. So this is one of the most fast pace events this year (after science word of cource) but you need to be able to get what you want in 10 seconds or leset beacuse some of the stations are honesety 20 things to do in 3 minutes so orginization is the key. Get to know your book and binder like idk your bff. This is very important especally in those over filled stations. Make sure your rescores arn't to much (I once saw a team carry a dictionary sized book and a STUFFED 3 inch binder, they spent almost all their time looking through that monster of a book and binder). As a rule of thumb '''keep it travel size" a 1 inch binder should be plenty and a fairly good book will do.

Rocks
There are three classifications of rocks: igneous, metamorphic, and sedimentary. Any type of rock can be transformed into the other kind. Igneous rocks are created from solidified magma (rock that has been melted inside the earth), sedimentary rocks are created when smaller bits of rock or sand are cemented together, and metamorphic rocks occur when other types of rocks are subjected to heat and pressure.

Igneous: There are two main classifications of igneous rocks: intrusive and extrusive.


 * Intrusive rocks hardened slowly, beneath the surface of the earth, and often formed large mineral crystals within the rock. Granite is a good example of an intrusive rock. A porphyritic intrusive rock is one which has large crystals embedded in a matrix of smaller crystals. Pegmatite is the only porphyritic rock on the Science Olympiad list.


 * Extrusive rocks hardened quickly during a volcanic eruption and are usually smooth-grained. Basalt is the most common form of extrusive rock.

Granite Intrusive Crystals of feldspar (pink or red), mica (dark brown or black), and quartz (clear pink, white, or black). Coarse-grained. Obsidian Extrusive Shiny black. Volcanic glass, has a conchoidal fracture (see explanation of cleavage and fracture below) Be careful, even Pegmatite Intrusive Same composition as granite but has very large, usually light crystals. Pumice Extrusive Very light gray. Also volcanic glass, but very light and bubbly. Only rock that floats. Rhyolite Extrusive Usually light grayish-pink. Made of the same minerals as obsidian and pumice, but did not cool as quickly. Scoria Extrusive Dark gray, red, or black. Composed of basalt that cooled very quickly with trapped air, so it is bubbly-looking.

Sedimentary
Sedimentary rocks occur when smaller bits of rock and sand are cemented together. Sedimentary rocks are either clastic or organic.


 * Clastic rocks, like sandstone, are formed from other rocks and minerals.
 * Organic rocks, like limestone and coal, formed from the bodies or shells of organisms.

Name Clastic or Organic Description Anthracite Coal 93-98% pure carbon Shiny, scaly black. onchoidal fracture. Can be used like black chalk. Arkose Clastic, formed mostly from feldspar Gray or pink. Coarse grained, looks like sandstone with redder tint (which is formed mostly of quartz). Bituminous Coal Organic, 50-65% carbon Black, not very shiny Well-jointed, splinters under pressure. Hardness--2 Breccia Clastic Conglomerate of sharp, angular fragments. Often forms after rockslides. Conglomerate Clastic Conglomerate of smooth, rounded fragments. Has the largest grain sizes. Often forms in riverbeds. Coquina Clastically formed organic fragments. Conglomerate of limestone shell fossils that are poorly cemented. Diatomite Organic Light tan, cream, or white. Extremely lightweight, lighter even than chalk. Called "fossil flour" because it easily falls apart into flour-like dust. Dolomite Clastic Light gray, yellowish, pinkish Contains a mixture of limestone, but is at least 50% dolomite (mineral) Often contains fossils. Lignite Organic Coal that retains fibrous, woody structure. Less than 50% carbon. Limestone  Composed of the fossilized shells of marine organisms. Chalk--White, soft, porous Crystalline--white, hard, crystalline Fossiliferous--fossil structures can still be seen in rock Oolitic--formed from small, round organisms that can still be seen individually Travertine--Color-banded, crystalline, often fibrous or concretionary. Sandstone  Even, medium-sized quartz grains Color variable, often tan, pink, or red. Shale  Very small, microscopic particles. Soft, and splits into plates Brown or black.

Metamorphic
Metamorphic rocks are composed of other rocks which have been subjected to heat and pressure. Often these rocks bear little resemblance to their parent rocks.

Name Parent Description Gneiss Can be formed of almost any other rock Medium to coarse grained. White or gray, but foliated with dark rock. Must be less than 50% foliated. High grade metamorphism Marble Calcite or limestone Fine to medium grained. White, can be patched with green, gray, brown, or red. The metamorphism of limestone or dolomite. Phyllite Slate Light, silvery-gray to lead-gray. Silky sheen Very fine grains, wavy bands. Schist Almost any rock. Silvery-gray, banded, wavy. Must be more than 50% foliated with dark rock. Garnet Schist: Contains fairly large garnet inclusions. Mica Schist: Very shiny because of diorite inclusions. Quartzite Pure sedimentary rocks White to patchy gray, fairly small particles. Can range from sugary green to gray to pink. The metamorphism of sandstone/ Slate Shale Dark gray, shiny Very small particles. Low grade Metamorphism.

Minerals
By definition, minerals must have a definite chemical and crystal structure. There are a huge variety of minerals, many of which are very common. In order to understand minerals, it is helpful to understand basic chemistry and the periodic table. I won't attempt to go over all of that here, just look it up in any chemistry book. Each mineral can be classified by ten different characteristics: group, formula, color, streak, luster, crystal structure, cleavage, fracture, hardness, and specific gravity.


 * Group-Minerals are organized into groups based on their chemical makeup. Native elements are composed of a single, pure element; Sulfides contain sulfur, arsenic, tellurium, or selenium; Oxides and Hydroxides contain oxygen compounds; Halides contain sodium, chlorine, fluorine, iodine, or bromine; Carbonates and Borates contain the carbonate or borate groups; Sulfates contain the sulfate group; Phosphates, Arsenates, and Vanadates contain one of those chemical groups, and the Silicates and Tectosilicates contain the element silicon.


 * Formula-Each mineral has a definite chemical composition. For example, fluorite is CaF2?. Again, if you need a review on chemical formulas, look in any chemistry textbook.


 * Color-Color is not a good way to identify a mineral!!! Some minerals can be any color under the sun. While color can sometimes be useful, don't rely on it!


 * Streak-Streak is the color you get when you rub a rock across an unglazed piece of porcelain. Streak is much more useful than color because a mineral always has the same streak.


 * Luster-A mineral's luster is the way it reflects light. Descriptions of luster are very subjective, but sometimes useful. Common types of luster are vitreous (glassy), adamantine (brilliant or gem-like), resinous (resin-like), greasy, pearly, waxy, and silky.


 * Crystal Structure-I can describe each type of crystal structure, but you should also get a good mineral book, like the Peterson Field Guide, and read the section on crystal structure.


 * Isometric-Three axes of symmetry, all at right angles to one another, and all of equal lengths.


 * Tetragonal-Three axes of symmetry, all at right angles to one another, two of the same length and one shorter.


 * Hexagonal (Trigonal)-Four axes of symmetry; three are of equal length and lie in the same plane at 120 degrees, the other can be any length and lies at right angles to the others.


 * Orthorhombic-Three axes, all at right angles to one another, of three different lengths.


 * Monoclinic-Three unequal axes, two at right angles, and the other inclined.


 * Triclinic-Three unequal axes, none of which are at right angles to any others.


 * Cleavage-When a mineral has the tendency to break along smooth, flat surfaces, it has cleavage. If the break is perfectly smooth and shiny, it is said to have perfect cleavage. Cleavage can also be described as good, distinct, or poor.


 * Fracture-Fracture is described as the way a mineral breaks (not along a cleavage plane). It can be uneven, hackly (sharp, jagged surface like broken metal), splintery, or conchoidal (shell-like).


 * Hardness-The Mohs Hardness Scale, which is used my most mineral collectors, is based on the hardness of other minerals. It is on a scale of one to ten, ten being the hardest. To test two minerals against each other, try to scratch each mineral with the other in an inconspicuous place. If they both scratch each other, they have the same hardness. If only one causes a scratch, it is the hardest. Or, you can use common objects to see if the scratch or can be scratched by a mineral.

1: Talc

2: Gypsum

2.5: Finger nail

3: Calcite

3: Copper penny

4: Flourite

5: Apatite

5.5: Knife blade

6: Feldspar

6: Window glass

7: Quartz

7: Steel File

8: Topaz

9: Corundum

10: Diamond


 * Specific Gravity-Specific gravity (SG) is a measure of how dense a mineral is. It compares the mass of one gram of the mineral to the mass of one gram of water. So, a mineral with a SG of 4.5 is 4.5 times as heavy as water. With practice, you can tell whether a mineral specimen is "light" (usually less that 3.5) or "heavy" (greater than 4). Specific gravity can be helpful in detecting metallic minerals (they are usually heavier), or in cases where a mineral is unusually heavy. For example, galena is a gray, metallic mineral with a high lead content, and it is noticeably heavy. It is especially useful in the case of barite, a white mineral which is unusually heavy because it contains the heavy metal barium, but does not look metallic at all.

I'm not going to go through and type the characteristics of every single mineral on the list. You can get all that information from any good mineral identification handbook. However, it is really helpful to know the one distinguishing characteristic of each mineral (in my opinion), or just a short description that helps me remember that mineral, so that's what I'll supply.

Mineral Name Description Albite White, tan, or cream feldspar

Almandine Dark red, garnet.

Amazonite Bright green feldspar.

Apatite Usually green or purple, but can be almost any color.

Aragonite white, powdery variety of calcite. Can often form amber colored hexagonal crystals.

Augite There's about six different minerals on the list that just look like nondescript black rocks. They're not much fun to tell apart. Augite is one of them. I usually identify it because it has a greenish tinge and cleavage at a right angle.

Azurite Always blue (I love those times when color actually means something), with a blue streak.

Bauxite Tan rock with orange, white, and prown pisoliths of aluminum, causing light weight. Formed from weathering of feldspars.

Barite White and kind of platy, but very heavy because it contains barium. Can form rosettes.

Beryl The cheap specimens we usually see in Science Olympiad are mostly light green and opaque. Often have hexagonal crystal. Aquamarine and Emerald

Biotite Black mica--it's thin and platy. It comes off in thin sheets.

Bornite "Peacock Copper." It has a dark, purplish-blue tarnish. Chalcopyrite, which looks almost the same, tarnishes purple, orange, yellow, and red.

Calcite Looks almost like fluorite and can be any color, but it's a little softer and it has a more rhombus like shape. It also bubbles in hydrochloric acid (HCl), but most people don't have that lying around to test rocks with.

Celestite Usually a soft, translucent white or blue.

Chalcopyrite Very brassy yellow, tarnishes bright red, purple, yellow, and orange.

Copper looks like�.well, copper. You can usually see the green tarnish.

Corundum very hard reddish or purplish rock. Very hard and often has small column-like opaque crystals. Rubies and Sapphires.

Diamond Adamantine luster. Comes in various lighter colors. Hardest mineral.

Dolomite You can often see thin, platy cream-colored crystals. Sometimes there are dark specks embedded between the crystals.

Epidote Mostly greenish-yellow and grainy, but can be almost any shade of green. Often confused with olivine. Described as "pistachio"

Feldspar Kind of a salmony-pink color. It has a very distinctive luster.

Flourite Almost any color. Hard to distinguish from calcite, but it's a little harder. Usually has dipyramidal or cubic stucture.

Galena One of my personal favorites. It has perfect cubic cleavage and is very heavy. It is made of lead sulfide and is a important lead ore.

Goethite Yet another dark indistinctive mineral that gives Science Olympians headaches. This one sometimes has a slightly iridescent tarnish, though. We knew it as the "ugly brownish orange-black rock"

Gold Gold is...well gold colored. Don't mistake with pyrite. Typically smoother than pyrite.

Graphite Silver, shiny, soft, and leaves dark smudges on your hands. Used for pencil lead.

Gypsum Looks like any number of transparent colorless minerals, but luckily gypsum is very soft and easily scratched with your fingernail. Alabaster gypsum is white and opaque, satin-spar is white and fibrous, and selenite is transparent.

Halite Rock Salt. About the color and hardness of selenite gypsum. It has nice cubic crystals, though, and you can usually identify it from that. Tasting specimens is against the rules in Science Olympiad, but smelling them is not and salt has a distinct smell along with a greasy feel.

Hematite Hematite will either be black and shiny, dark gray and dull, or rusty red. Its most distinctive feature is it's cherry red streak, but it also has one other interesting property. It is almost always cool to the touch, much more than magnetite (which it looks like).

Hornblende Black with short stubby crystals, and usually striated lengthwise.

Kaolinite Looks like chalk, but is actually clay. It is usually white and orange.

Lepidolite A very pretty pink or lilac color. It also has darker purple dots, called lamellae. A type of mica so it is sometimes found in sheets.

Magnetite Looks a lot like hematite, except it's magnetic. If you don't have the equipment to check for that, it has a gray or black streak. Hematite's streak is cherry-red.

Malachite This mineral is easy because it is always green, with a green streak. It is often found with azurite.

Muscovite White, yellow, or tan mica--thin and platy.

Olivine Usually light green or yellowish-green. Transparent specimens are called peridot.

Opal Precious opal is iridescent, but most opal is white and opaque with a greasy or waxy luster.

Pyrite Metallic fool's gold, often found in cubic or hexagonal crystals. It has a blackish green streak.

Quartz Fairly hard, no cleavage. Agate is often grey or brown and is banded, onyx is a black variety of agate, amethyst is purple and transparent, chalcedony is waxy, transparent grey and usually found in bulbous masses, chert/flint is white/black and noncrystalline with a marked conchoidal fracture, citrine is yellow or orange and transparent, crystal is colorless and transparent, jasper is orange or red and opaque, milky is crystalline but white or light tan, rose is pale pink.

Rhodonite Comes in all shades of pink and red. It's usually massive, but sometimes crystalline.

Silver Metallic silver color

Sodalite Always blue, but usually a very dark, mottled blue. It's darker color and colorless streak tell it apart from azurite.

Sphalerite Can be almost any color, but usually yellowish, tan, or reddish. It sometimes comes in crystals, but it can be massive, too when it is usually a dark brown. It has a resinous luster.

Staurolite Almost always forms short, prismatic crystals. It's usually brown, and sometimes forms cruciform twins.

Sulfur It's always some shade of yellow, and it gives off a sulfurous odor when rubbed.

Talc Very soft, often light green, white, or grey and feels very waxy.

Topaz Extremely variable color, but usually comes in well-formed prismatic crystals. A light colored gem

Tourmaline Also extremely variable when it comes to color, but it often comes in long prismatic crystals with vertical striations on it's surface.

Tremolite Usually comes in small, bladed crystals. It's light-colored and sometimes transparent. Commercially, tremolite was used as asbestos.

Ulexite Almost always white, and looks like a densely-packed bundle of white threads. It's opaque in one direction, and conducts light in the other. It's fiber-optic abilities gave it the nickname "T.V. rock."

Well, I hope this is helpful to everyone doing this event. If you want to be successful, don't just read this and expect it to tell you everything. Get a couple of good books and get to know them really, really well. Eventually you won't need the books for basic identification, but it's always good to keep them around just in case. I recommend the Peterson Field Guide to Rocks and Minerals, but my partner and I also use the Audubon book (the field guide, not the pocket guide) and the Eyewitness Handbook. If you're really serious, buy or borrow a college book on geology or mineralogy. There are also a lot of good internet resources. I'd suggest starting at http://www.minerals.net. It has good descriptions of minerals, and a lot of nice links. Good luck!

Valuable Links
Printable Cheat Sheet

Comprehensive Definition List