Rocks and minerals for Science Olympiad

muscovite

White, yellow, or tan mica--thin and platy Hardness: Streak: Color: Group: Crystal shape:

Shale, carbonaceous

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limestone, oolitic

..., A sedimentary rock texture characterized by sand sized spherical concretions of calcium carbonate deposited in a warm, shallow marine environment

sandstone

..., a sedimentary rock consisting of sand consolidated with some cement (clay or quartz etc.)

limestone, travertine

..., form of calcite that is deposited in terraces around the mouths of hot springs

bornite

Cu5FeS4 H 3.0, S.G. 5.06-5.08 Streak: gray-black Luster: metallic This beautiful purplish iridescence helps to identify this copper mineral . Sometimes called peacock ore. Untarnished bornite is golden colored a mineral consisting of sulfides of copper and iron that is found in copper deposits

Basalt

Basalt is a microcrystalline dark rock, with very little quartz. It sometimes appears in our recent lava flows as heavy, dark rock, often pitted with cells (gas bubble holes).

aragonite

CaCO3 H:3.5-4, S.G: 2.9-3.0 Color: white, light tan, or colorless. Bubbles in cold hydrochloric acid (HCl). Often occurs as a white branching, coral-like growth. Found in caves and near hot springs.

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. Hardness: Streak: Color: Group: Crystal shape:

marble

Coarse, crystalline; Parent rock was limestone or dolostone; Composed essentially of calcite or dolomite crystals; Used as a decorative and monument stone; Exhibits a variety of colors

Diorite

Coarse-grained igneous rock of intermediate composition. Up to half of the rock is plagioclase feldspar and the rest is ferromagnesian minerals.

rhodonite

Comes in all shades of pink and red. It's usually massive, but sometimes crystalline Hardness: Streak: Color: Group: Crystal shape:

azurite

Cu3(CO3)2(OH)2 H: 3.5-4.0. S.G. 3.8 Luster: Glossy Color: light blue to almost black. Azurite is identified by its blue color and low hardness. Most other minerals are much harder than this. Azurite is a carbonate that dissolves in HCL with bubbles given off. It is a secondary copper mineral.

Rhyolite

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slate

Shale when changed by heat and pressure will form into slate. Slate can be distinguished from shale by its being harder and heavier. Slate also shows the layering effect shale does.

talc

has a hardness of 1, can be scratched by a fingernail, is on the the Mohs Hardness scale,feels soapy when touched

graphite

lead gray, metallic luster, hardness of 1.5. Used as pencil "lead"

halite

naturally occurring crystalline sodium chloride. H 2.5, S.G. 2.1

garnet schist

shimmery gold — looks like flakes or little fish scales. Contains little garnets

Galena

soft blue-gray mineral

kaolinite

white gray to yellow brown, white streak, earthy dull, 2 hardness, no cleavage, compact and chalk like

staurolite

Almost always forms short, prismatic crystals. It's usually brown, and sometimes forms cruciform twins. Hardness: Streak: Color: Group: Crystal shape:

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". Hardness: Streak: Color: Group: Crystal shape:

tourmaline

Also extremely variable when it comes to color, but it often comes in long prismatic crystals with vertical striations on it's surface. Hardness: Streak: Color: Group: Crystal shape:

sodalite

Always blue, but usually a very dark, mottled blue. It's darker color and colorless streak tell it apart from azurite Hardness: Streak: Color: Group: Crystal shape:

Andesite

An intermediate colored rock, generally gray greenish-gray, also classed as an aphanite because of the small crystal or grain size.

topaz

Extremely variable color, but usually comes in well-formed prismatic crystals. A light colored gem Hardness: Streak: Color: Group: Crystal shape:

hematite

Fe2O3 H 5-6 S.G 5.26 Streak: red or reddish-brown. Luster: metallic black, gray, red, brown Hematite is the principle ore of iron. The hardness of hematite varies considerably If you suspect a specimen may be hematite, always check streak. The reddish-brown streak generally indicates some form of hematite.

Gabbro

Gabbro is a dark-colored, coarse-grained intrusive igneous rock. Gabbro is very similar to basalt in its mineral make up. It is composed mostly of the mineral plagioclase feldspar with smaller amounts of pyroxene and olivine.

Granite

Granite is an intrusive igneous rock with crystals large enough to identify the minerals. It is made of mica, quartz and feldspar. This is called a phanerite. In simple classification it is best to say that if you can identify quartz, the group name granite should be used. Grain size may be determined and this information in the name such as coarse-grained granite. Contains quartz, feldspar

bauxite

H 1-3 S.g 2-2.5 Luster: dull It is the main ore for production of aluminum. Note the obvious nodules.

gypsum alabaster

H 2.0, S.G. 2.3. Streak - white. Colorless transparent also grey and white. A rock-forming mineral in evaporative beds. Gypsum can be identified by its hardnes and white, tan or buff color. It forms in massive beds. Gypsum is made into sheetrock used in walls in homes.

biotite

H 2.5 (on cleavage, 4.0 across cleavage) S.G 2.8-2.9 Color: black or dark brown. Luster: vitreous, glassy. The perfect cleavage and the flexible and elastic sheets help to identify biotite as a mica. dark brown to black mica found in igneous and metamorphic rock

barite

H 3-3.5 S.G. 4.3-4.6 Streak: White, Color: white or colorless mineral (BaSO4). Can be bluish, yellow, brown or reddish. A heavy mineral that can be recognized by its specific gravity (SG). Quartz is harder and not as heavy

apatite

H 5.0, S.G. 3.1-3.2 Luster: vitreous, Color: colorless, white, brown, green, violet, blue or yellow. Hexagonal crystals and color help distinguish. Looks like Beryl, but not as hard. Used as source of phosphate in fertilizer.

beryl

H 8.0, S.G. 2.6-2.8 Luster: glassy Mostly occurs in pegmatite rocks. Has a hexagonal crystal shape. Colors vary from white, blue, yellow, green and pink. Hardness, color, crystal shape identify. Special gem names blue and blue-green: aquamarine, pink: morganite, green: emerald the chief source of beryllium

diamond

H: 10.0, very hard native crystalline carbon valued as a gem

copper

H: 2.5-3, S.G 8.94, Streak: Black, Luster: Metallic. Native copper looks how we think copper should look. Major deposits of native copper in Keweenaw Peninsula in Michigan.

calcite

H: 3.0 S.G. 2.7 Streak: White Luster: Glassy to vitreous Most easily identified because it dissolves in cold HCl acid with effervescence. Crystals take many shapes in hexagonal system.. Massive calcite is milky white, clear or golden brown. It can be distinguished from quartz by hardness and effervescence. a common mineral consisting of crystallized calcium carbonate. The mineral in stalactites in caves.

augite

H: 5-6, S.G: 3.2 - 3.6 The pyroxene group of minerals are very important as they are a major rock forming mineral. Can be identified by its two directional cleavage at nearly 90 degrees.

Actinolite

H: 5.5-6 SG:2.9-3.5 Actinolite ( Ca2(Mg,Fe)5Si8O22(OH)2) and Tremolite are two very similar minerals that form a series with each other and essentially share the same chemical formula. Actinolite has a greater presence of iron over magnesium, whereas Tremolite has a greater presence of magnesium over iron.

amazonite

H: 6.0, S.G: 2.5-2.6, Luster: Glassy-vitreous, Color: Green, white, flesh. The only green feldspar

Albite

H: 6.0, S.G: 2.63. A silicate (NaAlSi3O8) a widely distributed rock-forming feldspar. Generally white or light colore. Two directional cleavage.

corundum

H: 9.0, S.G 3.9-4.1. Luster: vitreous. Hardest on scale after diamond. very hard mineral used as an abrasive. Hexagonal crystal form.

almandine

H:6.5-7.5, S.G:4.31. Color deep purplish red. Usually found in metamorphic rock. a deep red garnet consisting of iron aluminum silicate

lepidolite

Hardness:2.5-4 Heft: 2.8 Color:Pink, lilac, purple Streak: white, grey Breakage: cleavage in two directions Luster: nonmetallic (vitreous) Other:small crystals and flaky

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 Hardness: Streak: Color: Group: Crystal shape:

pyrite

Metallic fool's gold, often found in cubic or hexagonal crystals. It has a blackish green streak Hardness: Streak: Color: Group: Crystal shape:

goethite/limonite

Metallic. H = 5 - 5.5. Streak: yellow -brown. Color dark brown to black; tarnishes yellow-brown; forms layers of radiating microscopic crystals.

gneiss

Metamorphic Rock

opal

Precious opal is iridescent, but most opal is white and opaque with a greasy or waxy luster Hardness: Streak: Color: Group: Crystal shape:

quartzite

Sandstone that has metamorphosed. It is difficult to determine the difference between sandstone and quartzite, but generally the following rule works. If a rock breaks through the sand grains it is quartzite. If it breaks around the grains it is sandstone. Quartzite is one of the hardest and most resistant rocks and is often used for building.

mica schist

Schist is the final process of change from shale to other rock by more heat and pressure. In a schist, the mica flakes have become completely aligned so that they appear in sheets or patches. Schist is often named by some mineral occurring in abundance.

malachite

This mineral is easy because it is always green, with a green streak. It is often found with azurite Hardness: Streak: Color: Group: Crystal shape:

tremolite

Usually comes in small, bladed crystals. It's light-colored and sometimes transparent. Commercially, tremolite was used as asbestos Hardness: Streak: Color: Group: Crystal shape:

olivine

Usually light green or yellowish-green. Transparent specimens are called peridot. Hardness: Streak: Color: Group: Crystal shape:

phyllite

a foliated rock that is intermediate in metamorphic grade between slate and schist, containing small crystals of mica and chlorite that give it more or less glossy sheen.

dolomite

a light colored mineral consisting of calcium magnesium carbonate

celestite

a mineral consisting of strontium sulphate

fluorite

a soft mineral (calcium fluoride) that is fluorescent in ultraviolet light

silver

a soft white precious univalent metallic element having the highest electrical and thermal conductivity of any metal

gold

a soft yellow malleable ductile (trivalent and univalent) metallic element

chalcopyrite

a yellow copper ore (CuFeS2) made up of copper-iron sulfide

sulphur/ sulfur

an abundant tasteless odorless multivalent nonmetallic element

feldspar

any of a group of hard crystalline minerals that consist of aluminum silicates of potassium or sodium or calcium or barium

epidote

colors are pistachio green, green, blackish-green, and brown. The color, hardness, and appearance are generally sufficient to identify this mineral

hornblende

green brown to black, white-gray streak, vitreous luster, 5-6 hardness, cleavage at an angle, bladed crystals