Chapter 2: Matter and Minerals

Mohs hardness scale

-A series of 10 minerals used as a standard in determining hardness. - a relative ranking scale

dark silicate minerals

-A silicate mineral that contains ions of iron and/or magnesium in its structure. -are dark in color and have a higher specific gravity than their counterparts

silicates

-Any one of numerous minerals that have the oxygen and silicon tetrahedron as their basic structure. -account for more than 90% of Earth's crust

Desnity

-Mass per unit volume - an important property of matter

nonsilicates

-Mineral groups that lack silicas in their structures and account for less than 10 percent of Earth's crust.

Garnet

-Much like olivine, has a glassy luster, lacks cleavage, and exhibits conchoidal fracture and is composed of individual tetrahedra linked by metallic ions. -Although the colors are varied, the mineral is most often brown to deep red, and in transparent form, it is used as a gemstone - when well-developed have 12 diamond shaped faces and are found in mica-rich metamorphic rocks

luster

-The appearance or quality of light reflected from the surface of a mineral.

rock-forming mineral

-The minerals that make up most of the rocks of Earth's crust.

specifc gravity

-The ratio of a substance's weight to the weight of an equal volume of water - most minerals have a value between 2 and 3

cleavage

-The tendency of a mineral to break along planes of weak bonding - this produces smooth flat faces of a mineral - when minerals break evenly in more than one direction this property is describes by the number of directions and the angles at which they meet

Amphibole

-any of a class of rock-forming silicate or aluminosilicate minerals typically occurring as fibrous or columnar crystals. -contains hornblende -double chain, cleavage at 60 and 120 degrees

Pyroxenes

-are a group of dark silicate minerals that are important components of dark-colored igneous rocks. The most common member, augite, is a black, opaque mineral with two directions of cleavage that meet at nearly 90-degree angles - structure is a single chain

Biotite

-e is the dark, iron-rich member of the mica family. Like other micas, biotite possesses a sheet structure that gives it excellent cleavage in one direction. -shiny appearance helps distinguish it from other dark silicate minerals. -Like hornblende, this is a common constituent of most light-colored igneous rocks, including granite.

olivine

-is an important group of dark silicate minerals (high-temperature minerals) that are major constituents of dark-colored igneous rocks like basalt. -Abundant(50%) in Earth's upper mantle, - is black to olive green in color, has a glassy luster, and often forms small crystals which gives it a granular appearance - no cleavage, structure is single tetrahedra

rock

-is any solid mass of mineral, or mineral-like, matter that occurs naturally as part of our planet. -aggregate implies that the minerals are joined in such a way that their individual properties are retained. ex. granite However, some are composed almost entirely of one mineral. ex. limestone-calcite - Some are composed on non-mineral matter ex. obsidian, pumice, coal.

hornblende

-is usually dark green to black in color (Figure 2.29B). Except for its cleavage angles, which are about 60 degrees and 120 degrees, this is very similar in appearance to augite. - this mineral forms more elongated crystals augite makes up the dark portion of otherwise lightcolored rocks - most common members of amphibole group

double refraction

-property of transparent mineral that produces a double image of an object viewed through them

mineral resources

- All discovered and undiscovered deposits of a useful mineral that can be extracted now or at some time in the future.

Potassium Feldspar (Orthoclase)

- One group of feldspar minerals contains potassium ions in its crystalline structure - usually light cream, slamon, or blue green -KAlSi3O8

crystal shape (habit)

- Refers to the common or characteristic shape of a crystal, or aggregate of crystals - aka crystal form - some minerals have more than one of these ex. pyrite

color

- one of the more ambigious properties of minerals - considered diagnostic property of very few minerals - often misleading in mineral identification

light silicate minerals

--A silicate mineral that lacks iron and/or magnesium. are generally lighter in color and have lower specific gravities than dark silicate -Contain varying amounts of aluminum, potassium, calcium, and sodium

Plagioclase Feldspar

-A feldspar containing sodium and/or calcium in addition to aluminum, silicon, and oxygen. - some of these will have striations which differentiate this mineral from Potassium feldspar - usually gray- blue-gray, to black - (Ca,Na)AlSi3O8 - sodium-rich plagioclase= albite = plagioclase feldspar showing striations= labradorite

tenacity

-A mineral's toughness or resistance to breaking or deforming

ore deposit

-A naturally occurring concentration of one or more metallic minerals that can be extracted economically. ex. Bingham Canyon Mine- mainly copper, but also gold silver and molybdenum

mineral

-A naturally occurring, inorganic crystalline material with a unique chemical composition.

nonrenewable resource

-A resource that forms or accumulates over such long time spans that it must be considered as fixed in total quantity. -Important metals such as iron, aluminum, and copper fall into this category, as do our most important fuels: oil, natural gas, and coal.

fracture

The way a mineral looks when it breaks apart in an irregular way - minerals having chemical bonds that are nearly equally strong in all directions exhibit this property

environment during crystallization and the chemical composition of the molten rock - Thus, by carefully examining the mineral makeup of rocks, geologists can often determine the circumstances under which the rocks formed.

What 2 factors determine which minerals are produced?

-are light silicates that typically form as products of chemical weathering of igneous rocks. -They make up much of the surface material we call soil, and nearly half of the volume of sedimentary rocks is composed of clay minerals. -Kaolinite is a common clay mineral formed from the weathering of feldspar -have a sheet structure

What are some characteristics of clay?

-The most abundant mineral group, comprising about 51% of Earth's crust -can form under wide range of temperatures and pressures -2 types: Potassium feldspar and Plagioclase felspar -All feldspar minerals have two directions of cleavage that meet at 90-degree angles and are relatively hard (6 on the Mohs scale). -

What are some characteristics of feldspars?

-e, is an abundant member of the mica family and has excellent cleavage in one direction. Muscovite is relatively soft -KAl(AlSi3O10)(OH)2

What are some characteristics of muscovites

-Halite NaCl Common salt Fluorite CaF2 Used in steelmaking Sylvite KCl Fertilizer

What are some examples of Halide minerals?

-Calcite CaCO3 Portland cement, lime, limestone Dolomite CaMg(CO3)2 Portland cement, lime, dolostone

What are some examples of carbonate minerals?

-A. Cleavage in one direction. Ex: Muscovite B. Cleavage in two directions at 90° angles. Ex: Feldspar C. Cleavage in two directions not at 90° angles. Ex. Hornblende D. Cleavage in three directions at 90° angles. Ex.Halite E. E.Cleavage in three directions not at 90° angles. F. Example: Calcite F. Cleavage in four directions. Ex.Fluorite

What are some examples of mineral cleavage?

Hematite Fe2O3 Ore of iron, pigment Magnetite Fe3O4 Ore of iron Corundum Al2O3 Gemstone, abrasive Ice H2O Solid form of water

What are some examples of oxide minerals?

Gypsum CaSO4 · 2H2O Plaster Anhydrite CaSO4 Plaster Barite BaSO4 Drilling mud

What are some examples of sulfate minerals

-Galena PbS Ore of lead -Sphalerite ZnS Ore of zinc -Pyrite FeS2 Sulfuric acid production -Chalcopyrite CuFeS2 Ore of copper -Cinnabar HgS Ore of mercury

What are some examples of sulfide minerals?

equant(equidimensional), bladed, fibrous, tabular, cubic, prismatic, platy, blocky, banded

What are some of the different types of crystal habits

1. Naturally Occurring 2. Generally inorganic 3. Solid Substance (ex. ice) 4. Orderly Crystalline structure ( exception: obsidian) 5. Definite Chemical Composition that allows for some variation -, the compositions of some minerals vary within specific, well-defined limits. This occurs because certain elements can substitute for others of similar size without changing the mineral's internal structure.

What are the 5 criteria that a substance must meet in order for it to be considered a mineral

-(SiO2) is the second-most abundant mineral in the continental crust - has bonds equal in all directions. is hard, resists weathering and does not have cleavage. - when broken, exhibits conchoidal fracture - when grown without interference, will develop hexagonal crystals with pyramid-shaped ends. - varieties of quartz include: milky(white), smoky(gray) rose(pink) amethyst(purple), citrine(yellow to brown) and rock crystal (clear)

What are the characteristics of quartz

-Nonmetallic minerals, such as quartz and halite, tend to be brittle and fracture or exhibit cleavage when struck. -By contrast, native metals such as copper and gold are malleable, and can be hammered into different shapes. -In addition, minerals, including gypsum and talc, that can be cut into thin shavings are described as sectile. -Still others, notably the micas, are elastic and will bend and snap back to their original shape after stress is released.

What are the different classifications of mineral tenacity

-tenacity, hardness, cleavage, and fracture

What are the different measures of mineral strength?

-When minerals fracture, most produce uneven surfaces and are described as exhibiting irregular fracture. -However, some minerals, such as quartz, break into smooth, curved surfaces resembling broken glass. Such breaks are called conchoidal fractures. -Still other minerals exhibit fractures that produce splinters or fibers that are referred to as splintery fracture and fibrous fracture, respectively.

What are the different types of fracture?

metallic luster- minerals that are shiny like a metal submetallic luster- Some metallic minerals, such as native copper and galena, develop a dull coating, or tarnish, when exposed to the atmosphere. Not as shiny as metallic luster vitreous luster- glassy luster dull/earthy luster- dull appearance like soil pearly luster- appearance like pearl silky luster- like satin cloth greasy luster- as if coated in oil

What are the different types of luster?

Carbonates, Halides, Oxides, Sulfides, Sulfates, Native Elements

What are the important classes of non-silicate minerals?

oxygen (O), silicon (Si), aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K), and magnesium (Mg).

What are the most abundant elements on Earth from least to greatest?

opague- no light is transmitted translucent- light but not image is transmitted transparent- when both light and image are transmitted

What are three classifications of minerals in how the differ in their ability to transmit light.

titanium and iron, chromium

What element makes sapphires blue and rubies red?

diagnostic property

a property of a mineral that aids in mineral identification. Taste or feel, crystal shape, and streak are examples of diagnostic properties - these properties are typically unique to one or only a few minerals.

silicon-oxygen tetrahedron

a structure composed of four oxygen atoms surrounding a silicon atom that constitutes the basic building block of silicate minerals

ambiguous properties

properties of minerals that may vary among different samples of the same mineral, such as color

streak

the color of a mineral's powder - is obtained by rubbing it across a ______plate (a piece of unglazed porcelain) - minerals that are harder than a ______ plate do not have this propery - metallic luster minerals have a dense dark _____ - nonmetallic luster minerals have a light-colored ______

Mineralogy

the study of minerals

renwable

A resource that is virtually inexhaustible or that can be replenished over relatively short time spans.

economic minerals

minerals used extensively in the manufacture of products

Augite

most common mineral in pyroxene group - is a black, opaque mineral with two directions of cleavage that meet at nearly 90-degree angles