Mineralogy Flashcards
8 elements of Earth;s crust
Oxygen Silicon Aluminum<br></br>Iron Calcium Sodium<br></br>Potassium Magnesium
Physical Properties for Mineral Identification
- Color<br></br>2. Luster<br></br>3. Hardness; fracture<br></br>4. Streak<br></br>5. Specific gravity<br></br>6. Cleavage<br></br>7. Crystal form
Least reliable trait for mineral identification
Color
Physical appearance
of the unweathered
surface. The Way it reflects sunlight
luster
Measure of the strength of the structure of the mineral relative to the
strength of its chemical bonds
Hardness
Is the resistance of a mineral’s smooth surface (face) to
being scratched by a point or an edge
Hardness
Mohs Scale of Hardness
Talc<br></br>Gypsum<br></br>Calcite<br></br>Fluorite<br></br>Apatite<br></br>Orthoclase<br></br>Quartz<br></br>Topaz<br></br>Corundum<br></br>Diamond
Hardness of fingernail
2.5
hardness of penny
3
hardness of knife blade
5.5
Color of a mineral in its ground or
powdered form
streak
ratio of a mineral’s mass to the mass of an equal volume of water
specific gravity
a break along a smooth, flat
plane producing smooth flat surfaces
called faces
cleavage
a break that is not smooth but
produces irregular surfaces
fracture
a description of the way a mineral tends to break
fracture
smooth curved fracture that is similar to a broken glass
conchoidal
similar to conchoidal, just not as curved but still smooth
subconchoidal
has sharp points or edges that catch on a finger that’s
rubbed across the surface.
jagged
a fracture type that occurs in fibrous or finely acicular
minerals
splintery
a fracture that produces a texture similar to broken children’s clay
earthy
result from the internal atomic arrangement of
a mineral
crystal form
repetition of crystal forms which produce the visible shape of the mineral
crystal system
minerals that have the same chemical composition, but different crystal formation
polymorphs
imaginary straight lines that pass through the center of the
crystal faces at right angles to these faces and intersect at the center
of a perfect crystal
axes
• 3 equal exes intersecting at right angles to
each other<br></br>• Same measure<br></br>• 6 faces<br></br>• Each face is a square<br></br>• Angle between two adjacent sides is 90 deg.<br></br>• Ex. Galena, halite, pyrite
Isometric or Cubic
Four axes<br></br>• 3 of the 4 intersect at 60oangles to others in the
same plane<br></br>• 4
th axis intersects the other 3 at a 90oangle<br></br>• Each of the similar 6 faces join each other at 60o<br></br>• 2 more identical faces are different form the other
6<br></br>• 2 identical faces form 90owith the other 6<br></br>• Ex. Calcite, quartz and apatite
Hexagonal
Two equal, horizontal,
mutually
perpendicular axes
(a1, a2)<br></br>• Vertical axis (c) is
perpendicular to the
horizontal axes and is
of a different length.<br></br>• All 3 axis intersect at 90 deg<br></br>• 2 of the 3 axis are of equal length<br></br>• Four identical often rectangular
faces and two square faces<br></br>• All adjacent faces hit at 90 deg<br></br>• Ex. Chalcopyrite, zircon
Tetragonal
• 3 axis intersect at 90 deg<br></br>• None of the axis are equal length<br></br>• Four of the faces form similar
rectangles<br></br>• 2 of the other faces are similar
rectangles but different from the
first 4<br></br>• All adjacent sides meet at 90 deg<br></br>• Ex. Olivine, sulfur, topaz
Orthorhombic
• 3 axes none of equal length<br></br>• Only 2 axes intersect at 90 deg<br></br>• 4 identical or similar faces<br></br>• 2 identical faces unlike the first 4<br></br>• 6 sided prism<br></br>• Faces meet at 90 deg and other
angles<br></br>• Ex. Mica, gypsum, orthoclase,
hornblende
Monoclinic
• 3 unequal axes
• None of the axes intersect at 90 deg
• Four similar or identical polygons and
2 larger similar or identical polygons
different form the first 4
• None of the faces intersect at 90 deg
• Ex. feldspars
Triclinic
The phenomenon wherein a mineral takes the
external shape of some other mineral or object
pseudomorphism
process that cause pseudomorphism whereinremoval of the atoms of the original object
and replacement with atoms of the other mineral
substitution
process that cause pseudomorphism whereone mineral encrusts or coats another. Then the
encrusted mineral may dissolve away leaving behind the encrusting
mineral as a pseudomorph
encrustation
process that cause pseudomorphism wherein conversion of one mineral to another by chemical
reaction usually involving the addition of water
alteration
process that cause pseudomorphism wherein after a polymorphic change, the
external shape of the previous polymorph may be retained
polymorphic transformations
subclasses of the silicate group
• Nesosilicates(single tetrahedrons)<br></br>• Sorosilicates(double tetrahedrons)<br></br>• Inosilicates(single and double chains)<br></br>• Cyclosilicates(rings)<br></br>• Phyllosilicates(sheets)<br></br>• Tectosilicates(frameworks)
•Structure possessing isolated
silicate tetrahedra
nesosilicate
Structure possessing double
island silicate tetrahedra
sorosilicate
Structure possessing parallel single
chains of silicate tetrahedra
inosilicate
Structure possessing isolated rings of
silicate tetrahedra
cyclosilicate
Structure possessing parallel sheets of
silicate tetrahedra
phyllosilicate
Structure possessing a three-dimensional
framework of silicate tetrahedra
tectosilicate
Common rock forming mineral<br></br>dark mineral and most common is hornblende<br></br>crystals are generally long and thin
amphibole
other common, light-coloured rock-forming mineral.<br></br>generally dull to opaque with a porcelain-like appearance
feldspar
red pink and white feldspar
orthoclase
green, grey and white feldspar
plagioclase
distinguished by its characteristic of peeling into
many thin flat smooth sheets or flakes.<br></br>the cleavage planes are in only one direction and
no right angle face joins occur
Mica
white and pearly mica
muscovite
dark and shiny mica
biotite
peridote in the jewellery trade<br></br>• yellow-green, translucent and glassy
looking.<br></br>• Crystals are not uncommon
<br></br>• usually occurs as rounded grains in
igneous rocks or as granular masses
olivine
generally dark green to black in
color <br></br>• forms short, stubby crystals
pyroxene
glassy looking, transparent or translucent mineral <br></br>• varies in color from white and grey to smoky. <br></br>• individual crystals are generally clear, while in
larger masses quartz looks more milky white. <br></br>• it can easily scratch a steel knife blade
quartz
common rock forming minerals
amphibole<br></br>feldspar<br></br>mica<br></br>olivine<br></br>pyroxene<br></br>quartz
mineral resources
aluminum<br></br>chrysotile<br></br>coal<br></br>copper<br></br>gold<br></br>potash<br></br>salt<br></br>zinc
relatively soft, silvery white metal with a dull luster<br></br>use are
transportation, building and construction, containers and packaging,
electrical, machinery and equipment
aluminum
a fibrous mineral with more than 2000 different uses.<br></br>• Qualities such as fire resistance, spinnability and tensile strength makes it an excellent material for brake linings in cars and aircraft to
pipes for water and sewer systems.
chrysotile
second only to oil in meeting the world’s energy
needs and critical input in the manufacture of steel
coal
• In nature, is usually associated with other metals
such as zinc, nickel, and gold.
• may occur in massive sulphide deposits or as porphyries.
• applications are in electrical transmissions, water tube,
castings and heat exchangers.
copper
valued for its extreme ductility, high resistance to corrosion, lustrous
beauty, and for its scarcity. <br></br>• The most familiar use of gold is the manufacture of jewelry, coins and
other ornamentation.<br></br>also used in electronics, dentistry and the aerospace industry.
The remainder is purchased by investors.
gold
one of the three most important nutrients to plants, which are
nitrogen, phosphorus and potassium.<br></br>About 4% of total production goes into the manufacture of soaps and
detergents, glass and ceramic products, and de-icing.
potash
Sodium chloride (NaCl), as it is known to the industry, is used
in the manufacture of chlorine, caustic soda and soda ash,
three of the most important products in the heavy chemical
industry.
salt
usually occurs in association with copper or lead or
both.<br></br>The greatest use is as a coating for iron and steel
products to make them resistant to rust and corrosion
zinc
A symmetrical intergrowth of two or more crystals of
the same mineral
twinning
type of twins -single planar surface
connecting twins
contact twins
type of twins -contact surface is
irregular; two twins
are interpenetrating
penetration twins
type of twinned crystal in which
two crystals of the same mineral grow together with
a 180° rotation about the crystallographic c-axis.
This results in a mirror image relationship between
the two halves of the twin.
carlsbad twin
type of twins -multiple twin
planes are not
parallel; radiating
cyclic twins
type of twins -multiple
planes are
parallel
polysynthetic twins
origin of twinning -accident of growth
growth twins
origin of twinning -caused by external
stress inducing twinning as deformation
deformation twinning
origin of twinning -due to
polymorphic change
transformation twinning
