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MINERALS
Exam each mineral carefully, making note of the diagnostic characteristics that make
identification of it possible. The numbers assigned to the minerals match the numbers
assigned to the mineral specimens (BUT ARE NOT LISTED IN NUMERICAL ORDER)
included with your VU lab kit from the bookstore. It will be necessary for you to learn
the name, a diagnostic trait, and the importance of each mineral for the Midterm Mineral
Exam AND class and subclass for the Final Rock Lab exam.
11. GALENA Lead sulfide (PbS). Commonly found in cubic
crystals, cubic cleavage, lead grey color, metallic luster, grey streak,
hardness 2.5, high specific gravity (7.4-7.6), ore of lead.
19. SPHALERITE Zinc sulfide (ZnS). Dodecahedral cleavage,
yellowish brown to brown color, typically resinous luster, typically
yellow streak, hardness 3.5-4, specific gravity 3.9-4.1, powder treated
with warm hydrochloric acid produces rotten egg smell, is the ore of
zinc.
13./14. MAGNETITIE An oxide of iron (Fe3O4). Magnetic, back
color, metallic luster, black streak, hardness 6, specific gravity 5.18, is
an ore of iron.
15. HEMATITE Iron III oxide (Fe2O3). Granular form dark grey to
black in color, earthy forms rust red, granular metallic luster, earthy
varieties dull luster, reddish streak, hardness 5.5-6.5, specific gravity
5.26, most important ore of iron.
37. BAUXITE Mixture of aluminum hydroxides. (Al(OH)3 Dull to
earthy luster, hardness 1-3, typically pisolitic (round pea-sized grains),
may be claylike, specific gravity 2-2.55, ore of aluminum.
22. PYRITE Iron sulfide (FeS2). Bright yellow color, metallic luster,
greenish black streak, commonly in cubic crystals, hardness 6-6.5,
specific gravity 5.02, ore of iron and source of sulfur for making
sulfuric acid. Called “Fools Gold” because of its color and luster.
3. CALCITE Calcium carbonate (CaCO3). Usually white to
colorless, rhombic cleavage, vitreous to earthy luster, crystals
transparent to translucent, may show double refraction (Iceland Spar),
hardness 3, specific gravity 2.72, reacts strongly to hydrochloric acid,
source of lime for use in soil treatment and manufacture of cement
and mortar.
8. BERYL-TOPAZ Aluminum silicate fluoride hydroxide.
Al2SiO4(F, OH)3 Lustre: Vitreous, Sub-Vitreous, Waxy, Greasy.
Color: Green, blue, yellow, white, pink, etc. Streak: White. Hardness
(Mohs): 7½ - 8. Used as an abrasive and gem stone (topaz)
9. CORUNDUM aluminium oxide (Al2O3) Cleavage: None. Help on
Color: Color: Blue, Red, Yellow, Brown, Gray. Help on Density:
Density: 4 - 4.1, hardness 9.0 . Corundum is frequently used as an
abrasive and is world famous as the mineral of rubies and sapphires
5. APATITE-TRIPHYLLITE carbonate-rich apatite/francolite:(
Ca5(PO4)3(O) -Color green, brown, blue, yellow, violet, colorless,
Streakwhite, Luster is vitreous to subresinous, Cleavage poor, Mohs
Hardness 5 , Diagnostic Properties color, crystal form, and hardness,
can be scratched with a steel knife blade Crystal System hexagonal.
Uses: The primary use of apatite is in the manufacture of fertilizer - it
is a source of phosphorus. It is occasionally used as a gemstone.
Apatite also serves as an index mineral of Mohs hardness scale with a
hardness of five.
20. BARITE (BaSO4) is a mineral consisting of barium sulfate.
Luster: Vitreous, Pearly. Diaphaneity (Transparency): Transparent,
Translucent, Opaque. Color: Colorless, white, yellow, brown,
hardness of 3-3.5. Barite is the main ore of the element barium. It is
also important in the manufacture of paper and rubber.
12. CHALCOPYRITE- is a copper iron sulfide mineral that
crystallizes in the tetragonal system. It has the chemical composition
CuFeS2. It has a brassy to golden yellow color and a hardness of 3.5 to
4 on the Mohs scale. Its streak is diagnostic as green tinged black.
Chalcopyrite is a copper iron sulfide. It is the most commonly
encountered copper mineral and is the most important ore of copper.
17. LIMONITE Limonite is an iron ore consisting of a mixture of
hydrated iron(III) oxide-hydroxides in varying composition. The
generic formula is frequently written as FeO(OH)·nH2O, although this
is not entirely accurate as the ratio of oxide to hydroxide can vary
quite widely. Limonite is one of the two principle iron ores, the other
being hematite, and has been mined for the production of iron since at
least 2500 BCE.
26. DOLOMITE Calcium magnesium carbonate (Ca Mg[CO3]2).
Usually pinkish but may be white, brown, or other colors, hardness
3.5-4, specific gravity 2.85, less vigorous reaction with hydrochloric
acid, vitreous to pearly luster, source of lime for soil treatment.
4. FLUORITE Calcium Fluoride (CaF2). Vitreous luster, octahedral
cleavage, often in cubic crystals, hardness 4, specific gravity 3.18,
transparent to translucent, variable colors, used as a flux and as a
source of fluoride for oral hygiene and the production of hydrofluoric
acid.
18. HALITE Sodium chloride (NaCl). White or colorless, cubic
cleavage, vitreous luster, transparent to translucent, salty taste,
hardness 2.5, specific gravity 2.16, used for table salt and source of
chlorine for chemicals.
2/16. GYPSUM (SELENITE) Hydrous calcium sulfate
(CaSO42H2O). Usually white or colorless, vitreous luster, transparent
to translucent, tabular crystal form, soft with hardness of 2, specific
gravity 2.32, three unequal cleavages, may show fibrous fracture, used
in dry wall and plaster, used for fertilizer.
29. KAOLINITE A hydrous aluminum silicate (Al2Si2O5[OH]4).
Soft with hardness of 2-2.5, usually dull luster, usually claylike
masses, looks earth, feels chalky, specific gravity 2.6-2.63, used to
make fine china and ceramics, used as a filler in paper r and paint.
30. OLIVINE Magnesium iron silicate ([Mg,Fe]2SiO4). Olive to
grayish or yellowish green color, vitreous luster, transparent to
translucent, conchoidal fracture, granular texture, hardness 6.5-7,
specific gravity 3.27-3.37, not of any real economic importance.
27. HORNBLENDE Ca2(Mg4Al) (Si7Al). A complex hydrous
silicate containing aluminum, calcium, magnesium, sodium, and
titanium. Vitreous to silky luster, dark green to black color, prismatic
cleavage, hardness 5-6, specific gravity 3.2, common rock-forming
mineral, no economic importance.
23./24. MICA (MUSCOVITE) A hydrous potassium aluminum
silicate (KAl3Si3O10[OH]2). Usually a light brownish color, basal
cleavage permitting it to be split into thin sheets which are very
flexible and elastic, vitreous luster, transparent to translucent,
hardness 2-2.5, specific gravity 2.76-3.1, used for electrical insulators,
heat insulation, windows in stoves, etc.
1. TALC Hydrous magnesium silicate (Mg3Si4O10[OH]2). Very soft
with a hardness of 1, greasy or soapy feerl, pearly to greasy luster,
micaceous habit, usually greenish to white in color, powdered form
used as a filler in paint, paper, and rubber, etc., used for talcum
powder and in ceramics.
6./28. FELDSPAR (ORTHOCLASE) Potassium aluminum silicate
(KAlSi3O8). Vitreous luster, white to reddish color, hardness 6,
specific gravity 2.57, prismatic cleavage which forms angle of 90
degrees. The feldspars a)re the most common rock-forming minerals
of Earth’s continental crust. Used to make porcelain and other
7. QUARTZ Silicon dioxide (SiO2). Conchoidal fracture, hexagonal
crystal form, vitreous luster, transparent to translucent, hardness 7,
specific gravity 2.65, usually colorless or white but impurities often
color it, no cleavage. Second most abundant rock-forming mineral of
Earth’s continental crust. Used as an abrasive, in glass
manufacturing, in electronics. Some forms are used as semiprecious
gems (amethyst, citrine, opal, etc.).
32. GARNET (ALMANDITE) Fe3Al2(SiO4)3 A complex silicate
containing aluminum, calcium, chromium, iron, and magnesium in
various combinations. Vitreous to resinous luster, commonly
dodecahedral crystal form, commonly reddish in color, hardness 6.57.5, specific gravity 3.5-4.3, used as a gem stone and for abrasives.
33. SULFUR (S) is a chemical element with symbol S and atomic
number 16. It is an abundant, multivalent non-metal. Under normal
conditions, sulfur atoms form cyclic octatomic molecules with
chemical formula S8. Elemental sulfur is a bright
yellow crystalline solid when at room
temperature. Uses Elemental sulfur is used in black gunpowder,
matches, and fireworks; in the vulcanization of rubber; as a fungicide,
insecticide. Light yellow when pure, sometimes amber when stained
with hydrocarbons; some slaglike volcanic specimens are reddish
from selenium contamination or grayish from arsenic
contamination. Luster resinous; hardness 2; specific gravity 2.02.1; fracture conchoidal; cleavage basal, prismatic, and pyramidal.
Brittle; translucent.
31. PYROXENE (AUGITE) (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6. A
complex silicate containing calcium, magnesium, iron, aluminum, is
various combinations. May have good prismatic cleavage, cleavage
angle of almost 90° distinguishes it from hornblende, green to dark
black in color, vitreous luster, hardness 5-6, specific gravity 3.2-3.4,
common rock-forming mineral, no economic importance.
34. GRAPHITE is a mineral and the chemical formula is (C) and its
composition is carbon. Color is black silver. Luster is metallic to dull.
Transparency crystals are opaque Crystal system is hexagonal; 6/m
2/m 2/m Crystal habits include massive lamellar veins and earthy
masses, and scaly granules in metamorphic rocks. Hardness is 1 – 2
Specific gravity is 2.2 Cleavage is perfect in one direction. Fracture is
flaky.Streak is black gray to brownish gray. Traditional demand for
graphite is largely tied to the steel industry where it is used as a liner
for ladles and crucibles, as a component in bricks which line furnaces
(“refractories”), and as an agent to increase the carbon content of
steel. In the automotive industry it is used in brake linings, gaskets
and clutch materials. Graphite also has a myriad of other uses in
batteries, lubricants, fire retardants, and reinforcements in plastics.
35. KYANITE is an aluminium silicate with the chemical formula
Al2SiO5. Kyanite is Used primarily in refractory and ceramic
products, including porcelain plumbing fixtures and dishware.
Kyanite is easily distinguished from sillimanite or andalusite by its
tabular, long bladed, acicular form and by bluish colour; and slightly
lower hardness than sillimanite and andalusite. Another important
property is its double hardness. Its specific gravity is 3 to 3.7.
36. VERMICULITE (Mg,Ca,K,Fe+2)3 (Si,Al,Fe+3)
4O10(OH)2C4H2O Cleavage: Perfect. Color: Colorless, Green,
Gray white, Yellow brown Hardness: 1 ½ to 2. Brake linings: finer
grades of exfoliated vermiculite are being used in brake linings
primarily for the automotive market. Also used in gardening to loosen
soil.
38. PYROLUSITE MnO2 Luster: Metallic, Dull, Earthy.
Diaphaneity (Transparency): Opaque. Colour: Black or very dark
grey. Streak: Black to grey, hardness 2-6 ½. Pyrolusite is used in the
manufacture of steel and manganese bronze; in dry cells; and as a
decolorizing agent in glass
39.MALACHITE Cu2(CO3)(OH)2 Malachite was used as a
mineral pigment in green paints from antiquity until about 1800.
Luster: Adamantine, Vitreous, Silky, Dull, Earthy. Diaphaneity
(Transparency): Transparent, Translucent. Colour: Bright green,
hardness of 3.9-4.0
ROCKS
Examine each rock carefully, making note of the diagnostic characteristics that make
identification of it possible. The numbers assigned to the rocks match the numbers
assigned to the rock specimens included with the lab kit. It will be necessary for you to
learn the name, class, and subclass of each rock as part of your Final Exam in Lab.
IGNEOUS ROCKS
ROCK TYPE: IGNEOUS SUB-CATEGORY: INTRUSTIVE
(COARSED-GRAINED TEXTURE)
44. GRANITE Quartz and orthoclase feldspar are the essential
minerals needed to form this rock. Hornblend or micas may be
present as accessory minerals. Granites are quartz rich light colored
rocks, usually red or light grey in color. Granite is the most abundant
rock of Earth’s continental crust.
47. DIORITE Feldspar and hornblende are the essential minerals
need to form this rock. Quartz if present, is present only in small
amounts. Mica may be present as an accessory mineral. Although
light colored minerals predominate, the dark minerals usually give the
rock a darker color than granite.
46. SYENITE Feldspar is the essential mineral needed to form this
rock. Hornblende, mica, and other dark minerals may be present
accessory minerals. Thus syenite differs from granite in containing
little or no quartz. Syenite is usually a light colored rock of redish or
light grey color.
49. GABBRO This course grained rock is dark green to black in color
because of the abundance of dark minerals which make it up. You will
need to examine the rock carefully in good light to see the crystals
which make it up. Grabbro is a very heavy rock.
ROCK TYPE: IGNEOUS SUB-CATEGORY: EXTRUSIVE
(FINE-GRAINED TEXTURE)
40. PUMICE Pumice is characterized by an abundance of holes
formed when trapped gases explode from the lava issuing from a vent
during a volcanic eruption. The rock cooled so rapidly that it has a
glassy texture. The rock is typically so light in weight that light
pieces of it will float in water. Pumice is light colored, and usually is
grey or reddish.
51. Pitchstone is a dull black glassy volcanic rock formed when
viscous lava or magma cools quickly. It is similar to but coarser
than obsidian. It is a volcanic glass with a conchoidal fracture (like
glass), a resinous lustre, and a variable composition. Its color may be
mottled, streaked, or uniform brown, red, green, gray, or black. It is
an extrusive rock that is very resistant to erosion.
52. ANDESITE Andesite is an extrusive igneous, volcanic rock,
of intermediate composition, with aphanitic to porphyritic texture.
50. TRAXHYTE PORPHYRYAn igneous rock, trachyte primarily
consists of alkali feldspars, but also contains plagioclase as well as
minor amounts of other minerals, such as olivine, biotite, and
pyroxene. It is commonly considered to form via the crystallization
and extraction of magnesium, iron, and calcium from a basaltic
magma.
45. PEGMATITE Pegmatite is a light-colored, extremely coarsegrained intrusive igneous rock. It forms near the margins of a magma
chamber during the final phases of magma chamber crystallization. It
often contains rare minerals that are not found in other parts of the
magma chamber.
41. SCORIA Scoria is characterized by an abundance of holes
formed when trapped gases explode from the lava issuing from a vent
during a volcanic eruption. The rock cooled so rapidly that it has a
glassy texture. Scoria differs from pumice by being darker in color
and heavier in weight due to the presence of darker, heavier minerals.
Unlike pumice, scoria will not float in water.
21. OBSIDIAN This rock looks like colored glass because of its
vitreous luster. Obsidian forms when hot lava is discharged rapidly
into water. The rock is characterized by conchoidal fracture such as
seen in quartz or manufactured glass objects when they break.
Obsidian is typically black or reddish brown in color.
46. SYENITE Syenite is a coarse-grained intrusive igneous rock of
the same general composition as granite but with the quartz either
absent or present in relatively small amounts (<5%).
43. FELSITE (RHYOLITE) Rhyolite is a fine-grained equivalent of
granite. A granitic magma that flows out onto the surface of Earth
solidifies more quickly than magma that cools below the surface, and
as a result the rock has a finer grained texture. Like granite, rhyolites
are light colored rocks, usually pinkish or gray, or even purple. Some
rhyolites show banding or layering which are flow structure ore
served in the rock.
42. BASALT Basalt is the fine-grained equivalent of grabbro. A
grabbroic magma that flows out onto the surface of Earth solidifies
more quickly than magma that cools below the surface, and as a result
the rock has a finer grained texture. Like gabbro, basalts are dark
colored, heavy rocks.
SEDIMENTARY ROCKS
ROCK TYPE: SEDIMENTARY
53. ARKOSE is a detrital sedimentary rock, specifically a type
of sandstone containing at least 25% feldspar. Arkosic
sand is sand that is similarly rich in feldspar, and thus the potential
precursor of arkose.
63./65. SHALE Shale forms from the consolidation and compaction
of clay-sized particles. Shale is commonly gray or black in color, but
it may be red, green, or other colors. Shale may break into thin
partings, or it may be massive. The hardness of shale can vary, but
often it can easily be scratched even with a finger nail. With increase
in particle size, shales grade into sandstones.
54./66. SANDSTONE (ALL SANDSTONES) This rock is formed
from the consolidation and compaction of sand, generally quartz sand.
The grains making up the sandstone are usually rounded, and the
grains may or may not be strongly cemented together. Poorly
cemented sandstones are called friable. Sandstone can be a a variety
of colors and may show cross-bedding or other depositional features.
With an increase in the presence of clay, sandstones grade into the
shales
62. CONGLOMERATE Gravels turned into solid rock are called
conglomerates. This rock contains the largest sedimentary particles
which may range up to the size of boulders. The pebbles, cobbles and
boulders are usually rounded. The interspaces between the pieces of
gravel are filled with smaller particles and cement. A variety of
colors are possible.
59. CHALK is a soft, white, porous sedimentary rock, a form
of limestone composed of the mineral calcite.
61. TRAVERTINE is a terrestrial sedimentary rock, formed by
the precipitation of carbonate minerals from solution in ground and
surface waters, and/or geothermally heated hot-springs
64. OOLITE (egg stone) is a sedimentary rock formed from ooids,
spherical grains composed of concentric layers. Ooids are most
commonly composed of calcium carbonate The mechanism of
formation starts with a small fragment of sediment acting as a 'seed',
e.g. a piece of a shell. Strong intertidal currents wash the 'seeds'
around on the seabed, where they accumulate layers of chemically
precipitated calcite from the supersaturated water.
55./58./57/60. LIMESTONE (All limestones) This rock is composed
largely of the mineral calcite with other minerals present as
impurities. Many limestones are formed from the consolidation and
compaction of lime muds containing shells. Limestones composed
mostly from shells are called coquina. Some limestones are the result
of the precipitation of calcite from seawater. Limestones can vary
greatly in texture from fine-grained to course-grained. The rock is
usually light gray or tan, but other colors are often seen.
56./75. COAL (All coals) Coal is formed from the deposition and
compaction of plant material deposited in swamps. There are a
number of grades of coal: peat, lignite (brown coal), bituminous (soft
coal), and anthracite (hard coal). Pressure ultimately determines the
grade or rank of the coal. The sample of bituminous coal is black in
color and may show both dull and shiny surfaces.
METAMORPHIC ROCKS
ROCK TYPE: METAMORPHIC SUB-CATEGORY:
FOLIATED
67. SLATE (All shales) This rock forms from a low grade
metamorphism of shale. Slate looks like shale, but is harder and
denser than that rock. The tendency of slate to easily split into flat
sheets is called slaty cleavage. Slate is typically black, but many other
colors are possible.
73. PHYLLITE Phyllite (fillite) represents a higher grade of
metamorphism than does slate. The layers which make up the rock
are thicker and may show wavyness which is not typical in slate. The
rock’s surface may also show a shine indicating the presence of very
small plates of mica. A variety of colors are possible.
71./72. SCHIST (All schists) Schist is a well foliated rock composed
of platy or flake-like minerals which are easily seen. This rock
represents an intermediate grade of metamorphism. The layers
making up the schist are wavy or contorted. The rock has a low
resistance to weathering.
74. GNEISS Gneiss (nice) results from high grade metamorphism of
sediments, and its composition is similar to that of granite. The
imperfectly foliated coarse-grained rock typically shows of minerals
in thick uneven and often contorted bands.
ROCK TYPE: METAMORPHIC SUB-CATEGORY:
NONFOLIATED
In your kit these are non-foliated, but sometimes they can be foliated.
69. QUARTZITE Quartzite is the metamorphic equivalent of a
quartz sandstone. The rock is much harder and tends to break through
the grains rather than around them. Many colors are possible.
Quartzite is very resistant to weathering and erosion.
68. MARBLE Marble is the metamorphic equivalent of a
limestone. Low grade metamorphism results in a fine textured rock,
while high grade metamorphism results in a coarse texture. Marble is
usually white or light pink in color, and streaks of other colors are
often present.
70. HORNFELS is the group designation for a series of contact
metamorphic rocks that have been baked and indurated by the heat
of intrusive igneous masses and have been rendered massive, hard,
splintery, and in some cases exceedingly tough and durable.