Minerals

Question 0

anhydrite

Answer 0

a granular, white, anhydrous (water-lacking) calcium sulfate (CaSO4).

Question 1

Andesite

Answer 1

A volcanic rock that in chemical composition is intermediate between basalt and granite.

Question 2

Aragonite

Answer 2

A calcium carbonate mineral (CaCO3) that differs from calcite in its crystal form. (Aragonite is orthorhombic rather than rhombohedral as in calcite.)

Question 3

Augite

Answer 3

A complex aluminous silicate of calcium, iron and magnesium, crystallising in the monoclinic system, and occurring in many igneous rocks, particularly those of basic composition. It is an essential component of basalt, dolerite and gabbro.

Question 4

Basalt

Answer 4

Highly mafic igneous volcanic rock, typically fine-grained and dark in color; rough volcanic equivalent of gabbro.

Question 5

Bowen’s Reaction Series

Answer 5

the sequence in which minerals crystallize from a cooling basaltic magma.

Question 6

Calcite

Answer 6

The crystalline form of calcium carbonate, showing trigonal symmetry and a great variety of mineral habits. It is one of the commonest of minerals in association with both igneous and sedimentary rocks.

Question 7

Carbonate clasts

Answer 7

sand or gravel sized pieces of carbonate. The most common clasts are either bioclasts (skeletal fragment of marine invertebrates) or ooids (Fig 4-39 C), which are spherical grains formed by the precipitation of carbonate around a nucleus.

Question 8

Carbonate spar

Answer 8

clear, crystalline (sparry) carbonate. It occurs between clasts as a cement.

Question 9

Chert

Answer 9

A dense, hard sedimentary rock or mineral composed of sub microcrystalline quartz. Unless colored by impurities, chert is white, as opposed to flint, which is dark or black.

Question 10

Chlorite

Answer 10

A group of allied minerals which may be regarded as hydrated silicates of aluminium, iron and magnesium. They crystallise in the monoclinic system and are green in colour. They occur as alteration products of such minerals as biotite and hornblende, and also in schistose rocks.

Question 11

Clastic sediment

Answer 11

sediment consisting of broken or eroded pieces of pre-existing rocks or minerals.

Question 12

Clay mineral

Answer 12

silicates of hydrogen,aluminum,magnesium,iron, and potassium. Their basic structure is similar to that of mica but individual flakes are extremely small (some are as small as viruses). This means their mica-like form can be seen only with an electron microscope (Fig 4-15). Clay minerals form as a result of weathering of other aluminosilicate minerals, such as feldspars.

Question 13

Cleavage

Answer 13

the tendency of a mineral to break evenly along one or more bright, planar surfaces.

Question 14

Color

Answer 14

A mineral’s most conspicuous characteristic.

Question 15

Coal

Answer 15

black, soft rock made of carbon. Coal originates from the compressed, lithified remains of dead leaves, stems and trunks of plants that grew in a swampy environment.

Question 16

Contact metamorphism

Answer 16

metamorphism caused by heat from a nearby igneous intrusion. Contact metamorphic rocks are generally not foliated.

Question 17

Continuous series

Answer 17

Because the plagioclase minerals maintain the same basic crystal structure but change continuously in their content of calcium and sodium, the right side of the diagram is called the continuous series.

Question 18

Crystal habit

Answer 18

the way a mineral has grown by means of regular additions of ions to its surfaces from a liquid solution, a gas or molten rock.

Question 19

Density

Answer 19

Its mass per unit volume (density=mass/volume). Density is a reflection of the relative “heaviness” of a mineral

Question 20

Diorite

Answer 20

A relatively coarse-grained intrusive rock containing less silica than granite or granodiorite. It is composed primarily of plagioclase feldspar.

Question 21

Discontinuous series

Answer 21

The left side of the diagram depicts reactions that result in minerals of distinctly different structure. It is therefore called the discontinuous series.

Question 22

Dolomite

Answer 22

Either the magnesium-bearing carbonate mineral CaMg(CO3)2 or the rock that is composed largely of that mineral.

Question 23

Evaporite

Answer 23

water-soluble, mineral sediments that result from the evaporation of bodies of surface water.

Question 24

Extrusive igneous rock

Answer 24

mode of igneous volcanic rock formation in which hot magma from inside the Earth flows out (extrudes) onto the surface as lava or explodes violently into the atmosphere to fall back as pyroclastics or tuff.

Question 25

Feldspar

Answer 25

group of most common minerals of the Earth's crust. All feldspars contain silicon, aluminum, and oxygen and may contain potassium, calcium and sodium.

Question 26

Ferromagnesian silicate mineral

Answer 26

iron/magnesium bearing mineral, such as augite, hornblende, olivine or biotite.

Question 27

Foliation

Answer 27

parallel alignment of textural and structural features of a rock.

Question 28

Fractional crystallization

Answer 28

The separation of components of a cooling magma by sequential formation of particular mineral crystals at progressively lower temperatures.

Question 29

Gabbro

Answer 29

dark, coarse-grained, intrusive igneous rock chemically equivalent to basalt.

Question 30

Garnet

Answer 30

metamorphic index mineral. Forms at middle to high temperatures and pressures.

Question 31

Gneiss

Answer 31

course-grained metamorphic rocks. Its often dramatic foliation results when high pressure segregates minerals into bands rich in quartz, feldspar, biotite, or hornblende.

Question 32

Granite

Answer 32

a silica-rich, relatively light-colored intrusive rock.

Question 33

Granodiorite

Answer 33

quartz-bearing igneous rock in which plagioclase is the dominant feldspar mineral.

Question 34

Greenstone

Answer 34

a dark-green metamorphic rock. Except for a relatively few scattered larger crystals, most of the mineral components cannot be seen without magnification. Greenstones are formed during low-grade metamorphism of basaltic rocks.

Question 35

Gypsum

Answer 35

a soft, hydrous calcium sulfate (CaSO4 - 2H2O) that occurs as several varieties.

Question 36

Halite

Answer 36

(NaCl) is easily recognized by its salty taste and the fact that it crystallizes and cleaves to form cubes, as shown in the left-hand specimen in Figure 4-16.

Question 37

Hardness

Answer 37

in minerals, hardness is gauged by which materials scratch which materials, or are scratched in return.

Question 38

Hornblende

Answer 38

a black amphibole with a shiny luster. Hornblende is a silicate mineral that is common in rocks that form at high temperatures such as granite, diorite, or amphibolite.

Question 39

Hornfels

Answer 39

a type of hard metamorphic rock created by the heat of contact metamorphism. The protolith of hornfels was typically a fine-grained sedimentary or volcanic rock. (Such as shale).

Question 40

Igneous rock

Answer 40

rocks that form from magma, lava or tephra.

Question 41

Intrusive igneous rock

Answer 41

body of igneous rock that has crystallized from molten magma below the surface of the Earth.

Question 42

Lava

Answer 42

molten rock expelled by a volcano during an eruption.

Question 43

Lithification

Answer 43

the process in which sediments compact under pressure, expel connate fluids, and gradually become solid rock.

Question 44

Luster

Answer 44

the manner in which the surface of a solid reflects light.

Question 45

Mafic silicate

Answer 45

ferromagnesian mineral

Question 46

Magma

Answer 46

molten rock that is a mixture of molten silicates and gases.

Question 47

Marble

Answer 47

limestone that has been metamorphosed. Under pressure, all of the calcite in the original limestone is recrystallized. Any vestige of fossils in the limestone is eradicated. Note that there is no chemical change: Calcite (CaCO3) is the principal mineral in both limestone and marble.

Question 48

Metamorphic index material

Answer 48

form under specific temperature and pressure conditions. Geologists use them to determine the growth history of ancient mountain regions, even where only deeply buried "mountain roots" remain.

Question 49

Metamorphic rock

Answer 49

rock that forms by recrystallization of a pre-existing rock due to changes in temperature, pressure, or fluids in the rock.

Question 50

Metamorphism

Answer 50

the process that create metamorphic rocks.

Question 51

Mica

Answer 51

silicate minerals easily recognized by their perfect and conspicuous cleavage along a single pane.

Question 52

Micrite

Answer 52

exceptionally fine-grained carbonate mud.

Question 53

Mineral

Answer 53

A naturally occurring element or compound formed by inorganic processes that has a definite chemical composition or range of compositions, as well as a distinctive properties and form that reflect its characteristic atomic structure.

Question 54

Nonsilicate mineral

Answer 54

They do not contain the silicon-oxygen structures that characterize silicate minerals.

Question 55

Nonfoliated metamorphic rocks

Answer 55

Non-foliated metamorphic rocks are formed from mineral grains lacking any particular alignment. Such random arrangement of minerals occurs during metamorphism in two ways. First, when rocks are exposed to elevated temperatures – in the absence of any directed forces – mineral grains are free to grow with any orientation. Thus, non-foliated rocks are always produced by lithostatic pressure. However, non-foliated rocks can also form in another way. If the precursor rock consists of equant sized grains – grains with shapes that have similar lengths, widths, and heights – then the application of directed force fails to produce any preferential orientation. Thus, rocks containing largely spherical or cubical shaped grains will not produce a foliated texture, no matter the intensity of the directed pressure.

Question 56

Obsidian

Answer 56

an extrusive rock that cools too fast to form even small crystals. The magma that forms obsidian quickly solidifies to form a natural glass (Fig. 4-23). Obsidian forms from lavas that have lost most of their dissolved gasses, so it does not contain bubbles.

Question 57

Olivine

Answer 57

this glassy looking iron and magnesian silicate often has an olive green color ( Fig 4-14). It is present in dark rocks such as basalt

Question 58

Ooid

Answer 58

spherical grains formed by the precipitation of carbonate around a nucleus.

Question 59

Oolite

Answer 59

Limestone made of ooids.

Question 60

Partial melting

Answer 60

Occurs when rock that is subjected to high temperature and pressure is only partially melted and the liquid component moves to another location.

Question 61

Phyllite

Answer 61

regional metamorphic rock similar to slate except that the foliation surfaces are shinier and more wrinkled. Forms at slightly higher metamorphic grade (higher temperature) than slate.

Question 62

Pluton

Answer 62

having to do with intrusion of magma within the earth. Also called intrusive. Contrasts with volcanic, which has to do with extrusions of magma onto the earth's surface as lava or tephra.

Question 63

Plutonic igneous rock

Answer 63

rocks that form from intrusions of magma within the earth. Examples include granite and gabbro. Plutonic rocks are a sub-category of igneous rocks.

Question 64

Porphyritic texture

Answer 64

Rock that is porphyritic, containing large and small crystals, or, in mining, a specific deposit containing widely disseminated metals, typically copper.

Question 65

Pumice

Answer 65

White or creamy white highly vesicular rock, weathers to a pale brown on its surface. Very low density.

Question 66

Quartz

Answer 66

a very common mineral that is relatively hard and tends to fracture like broken glass. Quartz is a silicate mineral, made of the elements silicon and oxygen.

Question 67

Regional metamorphism

Answer 67

metamorphism in which a large volume of crust is subjected to stress and heat, forming foliated metamorphic rocks.

Question 68

Rhyolite

Answer 68

felsic volcanic rock that originates as a lava flow. Rhyolite commonly has a white or pink color. Rhyolite comes from magma that originates in the crust.

Question 69

Schist

Answer 69

regional metamorphic rock with foliation that is due to parallel flat minerals, especially mica minerals such as biotite or muscovite, with crystals big enough to see with the naked eye.

Question 70

Sedimentary rock

Answer 70

rocks that form from accumulated sediment.

Question 71

Sillimanite

Answer 71

indicates the highest level of temperature and pressure.

Question 72

Slate

Answer 72

the regional metamorphism of shale. (the foliation is microscopic and is caused by the parallel alignment of minute flakes of silicates such as mica.

Question 73

Strata

Answer 73

changes in conditions of deposition that cause materials of somewhat different composition or particle size to be deposited for a period of time. Sediment is deposited in layers that are originally horizontal.

Question 74

Streak

Answer 74

color of a mineral when it is ground to powder.h

Question 75

Texture

Answer 75

refers to the size and shape of individual grains and their arrangement in the rock.

Question 76

Tuff

Answer 76

A rock formed of compacted volcanic fragments, some of which can be distinguished by the naked eye. If the fragments are larger than the rock grades into an agglomerate.

Question 77

Vesicles

Answer 77

lava contains dissolved gases, bubbles will form small cavities