MINERALS ARE THE BASIS FOR MODERN SOCIETY Per capita use of amounts to several thousand pounds. Much of your house is mined from the . After “Out of the Rock” by the National Energy Foundation INDUSTRIAL MINERALS AROUND THE HOUSE Minerals are used around the house in many common products.



Glass/Ceramics Silica sand, , , lithium, borates, soda ash,

Vinyl Flooring , clay,

Glossy Paper Kaolin clay, limestone, sodium sulfate, , soda ash, titanium dioxide

Cake/Bread , phosphates

Plant Fertilizers Potash, phosphates, nitrogen,

Toothpaste Calcium carbonate, sodium carbonate, fluorine

Lipstick Calcium carbonate, talc



Hair Cream Calcium carbonate

Counter tops Titanium dioxide, calcium carbonate, aluminum hydrate

Household Cleaners Silica, pumice, diatomite, feldspar, limestone

Caulking Calcium carbonate, gypsum

Jewelry Precious and semiprecious stones

Kitty Litter Attapulgite, montmorillonite, , diatomite, pumice, volcanic ash

Fiberglass Roofing Silica, borates, limestone, soda ash, feldspar

Potting Soil Vermiculite, perlite, gypsum, zeolites, peat

Paint Titanium dioxide, kaolin clays, calcium carbonate, , talc, silica Minerals are also used at your school.

After “Out of the Rock” by the National Energy Foundation Minerals are in your teeth, bones, and even kidney stones.

Specimen courtesy of D. Cook, University Department of Anthropology All minerals are made of naturally occurring elements. ELEMENTS AND MINERALS collection of unit cells

unit cell atoms molecule

This diagram shows the relationships between atoms: atoms form molecules which come together in minerals as a collection of unit cells. Unit cells form minerals and visible crystal forms. After , 1998, Dexter Perkins STRUCTURE

Hard, bright, gem

Soft, gray, lubricant

The arrangement of atoms is important. The element (C) can form diamond -- a hard, clear mineral -- or graphite -- a soft, gray mineral -- depending on the . DEFINITION of MINERALS and ROCKS

A naturally occurring, generally inorganic Mineral: solid that has an ordered arrangement of atoms and specific chemical and physical properties.

1. Naturally occurring: Not man-made (but there are synthetic “gems”)

2. Solid: Hard; not liquid or gas

3. Ordered arrangement of atoms: Made of atoms that are arranged in three dimensions; crystalline

Is made of one or more minerals, usually Rock: occurring in large masses. ROCK CYCLE TYPICAL ROCK TEXTURES


Crystalline Fragmental Foliated (interlocking) (clastic) (banded) IDENTIFYING MINERALS Properties used by geologists Shape: Symmetry, form, habit, twinning : Tendency to break along the rows of atoms; shiny, flat fractures Hardness: Resistance to scratching Mohs Hardness Scale (from softest to hardest) 1. Talc 6. Feldspar 2. Gypsum 7. 3. 8. 4. 9. Corundum 5. Apatite 10. Diamond Density: Weight (relative to equal volume of water) Appearance: Transparency, color, luster, : Color of the fine powder from a mineral Special Properties:

1. Magnetism 4. Chemical reactions 2. Optical properties 5. Action in heat/flame 3. Electrical properties 6. Taste One way to help identify rocks is to use a “scratch hardness .” The items listed on the right side will make a visible scratch on any of the minerals listed above them. MOST COMMON INDIANA MINERALS


The most common Indiana mineral is calcite or calcium carbonate (CaCO3). Crystal structure of calcite. When allowed to freely grow into open spaces minerals can form beautiful geometric solids called . CALCITE

rhombohedral cleavage fragment

Calcite is calcium carbonate. It fizzes in . It is usually or colorless, but can be other colors because of impurities in it. It may have many outward shapes, but always breaks into little pieces shaped like rhombo- hedrons. Calcite makes up the rock called LIMESTONE. Limestone is used as fertilizer, , building stones, and to make cement. Crystals of calcite with trigonal pyramids. A vug (open space in rock) with iridescent calcite crystals in a limestone rock. Calcite crystals can also be found in geodes. A related mineral with the same chemistry as calcite but a different crystal structure is aragonite which forms white, needle-like crystals. Indiana limestone dissolves in acidic groundwater. These solution features are often seen in dimension limestone quarries. Indiana has many formations in limestone rock, called . Speleothems are made of calcite or aragonite. DOLOMITE

Curved faces

Pearly luster

Dolomite is calcite with added. It fizzes in warm acid. It is usually pink or white and has curved faces. It is a common mineral and is used for building stones and for making heat-resistant bricks for furnace linings. Example of dolomite in pink crystals with purple fluorite crystals. FLUORITE

Cubic crystals Octahedral cleavage

Often zoned

Fluorite is calcium fluoride (CaF2). It will change color under fluorescent light; this property is called . It is usually purple, light green, yellow, or clear. It forms in cubes, but cleaves into octohedrons. It is used for a flux in smelting , for decorative stones, in the chemical industry, and for making optical equipment. Yellow fluorite with white calcite


Fluorite This is a sample of a rare, fibrous form of fluorite. White gypsum and purple fluorite The mineral siderite (FeCO3) forms . This one also contains white clay minerals. Magnified image of quartz geode containing a barite (BaSO4) crystal. Delicate blue celestite (SrSO4) crystals Crystals display special features inside. Here, a pointy, white phantom crystal is inside the clear calcite. Petroleum is included in this calcite crystal giving it a brown color. This calcite sample has inclusions of a dark mineral, marcasite. Chert, a very fine-grained variety of quartz (SiO2), was used extensively by Native Americans.

chert spear point Crystals of quartz are common in geodes. This is a geode cut in two. The outside of geodes are bumpy and have spherical forms. This is a typical geode in the limestone bedrock. PYRITE

Brassy yellow

Dark tarnish

Pyrite (FeS2) is iron sulfide. It is also called “fool’s ” because it is a metallic golden color. Harder than gold, sparks will fly if it is hit with a hammer. It forms in cubes, and is not valuable by itself. are often replaced by pyrite. Pyrite is the most common in Indiana. This pyrite occurs in a black oil . Good crystals of pyrite are common. More typical occurrences of pyrite are in crystalline groups like these. This sample shows pyrite in limestone. Marcasite is also iron sulfide, but forms in a different crystal form as a of pyrite. The brown mineral sphalerite (ZnS) forms very large crystals in some cases. This crystal is about one foot long. Sphalerite also occurs in bands. Here, sphalerite and pyrite form the bands. The shiny, cubic mineral galena (PbS) is rare in Indiana. The rare mineral millerite (NiS) is the spidery, dark crystal growing upon quartz in this geode. Iron oxide such as this was used for red pigment by Native Americans. Small crystals of resistant, so-called “heavy minerals,” including gold (Au), can be concentrated from stream . These minerals were brought to Indiana by glaciers. The calcite crystal pictured here is from Indiana. The journal Rocks and Minerals featured Indiana minerals in this 1986 issue. Contact: Indiana Geological Survey An institute of Indiana University https://IGWS.indiana.edu [email protected] (812) 855-7636