Download Lab #3

JEO253-Min-Pet
Assoc. Prof. Meral Dogan
Dr. Dogan’s homepage
Lectures 3
Jeoloji Muhendisligi
Office:
213
Office Hours:
Office Phone:
297 77 28
Email Address:
[email protected]
Lab Syllibus
Lab #1: Measurement of Physical Properties of Minerals.
Lab #2: Introduction to the lattice, unit cell, and Miller indices.
Crystal systems, classes, and forms.
Lab #3: Crystal systems and crystal classes (continued).
Lab #4, 5 and 6: Tectosilicates, Phyllosilicates, Inosilicates,
Cyclosilicates, Sorosilicates, and Nesosilicates
Lab #7: Carbonates, Halides, Phosphates, Sulfates carbonates
Lab #8: Native elements, oxydes and hydroxytes
Lab #9: Magmatic rocks
Lab #10: Magmatic rocks
Lab #11: Sedimentary rocks
Lab #12: Metamorphic rocks
Mineral idendification
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Renk-Color
Parlaklık-Luster
Transparency (or diaphaneity)
Kristal sistemleri-Crystal Systems
Olusum formlari-Technical Crystal Habits
Descriptive Crystal Habits
Ikizlenme-Twinning
Dilinim-Cleavage
Kırılma-Fracture
Sertlik-Hardness
Specific Gravity
Cizgi rengi-Streak
Birlikte bulundugu mineraller-Associated Minerals
Color
 Usually, we notice the color of a mineral first. Some
minerals are easily identified by color because they are
never any other color. For example, malachite is always
green.
 Keep in mind, however, that color by itself isn't enough to
identify a mineral. Chemical impurities can change the
color of a mineral without changing its basic make-up. For
example, quartz in its purest form is colorless and clear as
glass. Quartz with traces of iron becomes violet (amethyst).
With traces of manganese, it turns pink (rose quartz). If
quartz is exposed to radiation, it turns brown (smoky
quartz).
Kuvars-quartz (SiO2)
Fluorit (CaF2)
labrodorite
 color
çizgi rengi-Some minerals leave a streak similar to
their natural color, such as cinnabar and azurite
 Cinnabar
Azurite
American Museum of Natural History
The terms used to describe luster (parlaklık)
 (Metalik) Metallic -- example: gold )
 (Camsı)Vitreous (glassy) -- example: quartz, tourmaline
 (Işıltılı) Adamantine (brilliant) -- example: diamond )
 (Reçine) Resinous (like resin or sap from a tree) -- example: sphalerite )
 (Yağsı) Greasy or waxy -- example: turquoise)
 (İncimsi) Pearly -- example: talc)
 (İpeksi) Silky -- example: asbestos)
 (Toprağımsı) Dull or earthy -- example: bauxite)
Metallic -high reflectivity like metal
 Galen (PbS)
 Sulfit
Dull/earthy -shown by finely crystallized minerals
 Hematit (Fe2O3)
 Oksit
Mohs' Hardness Scale
1-Talc
2-Gypsum
3-Calcite
4-Fluorite
5-Apatite
6-Orthoclase
7-Quartz
8-Topaz
9-Corundum
10-Diamond
Steel file
Gypsum (CaSO4. 2H2O)
 Jips
 Sulfat
Calcite-CaCO3
 Crystal
 (smooth
 faces)
Elmas-Diamond
 Crystal
 Reflection
Common Objects and Their Hardness Values
 2.5 Fingernail
 3.5 Penny
 5.5 Glass
 6.5 Steel knife
 An unknown sample can not be scratched by your fingernail (2.5) but it
can be scratched by a penny (3.5), then it's hardness is between 2.5 and
3.5. An example of a mineral that has a hardness between 2.5 and 3.5 is
calcite (3).
Specific Gravity
 is a special case of relative density defined as the ratio of the density of
a given substance, to the density of water when both substances are at
the same temperature.
 Substances with a specific gravity greater than 1 are more dense than
water, and those with a specific gravity of less than 1 are less dense than
water.
MineralsDensity
Specific gravity
 sulfur, graphite
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light
gypsum, quartz
medium
fluorite, beryl
medium -heavy
corundum, most metal oxides
heavy
native gold, platinum
heaviest
1-2
2-3
3-4
4-6
19
Ağır mineraller-Heaviest mineral
 Gold
Kristal sekilleri-Crystal forms
 Cubic
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tetragonal
hexagonal
Tuz-Halite (salt) (NaCl)
 Cubic (intergrown)
Pirit-Pyrite (FeS)
 cubic
Işınsal-Radiating habit
 marcasite
Klivaj-Dilinim (Cleavages (images web site))
Fracture describes how a mineral breaks when
broken contrary to its natural cleavage planes.
 Chonchoidal fracture (quartz) is a smooth curved fracture with
concentric ridges of the type shown by glass.
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 fibrous or splintery (tremolite),
 Hackley (copper), is jagged fracture with sharp edges.
 Irregular
Parting in Minerals
 Parting is a property that often gets confused with cleavage.
 There is good reason for that. Parting is a break along structural planes
and is parallel to a possible face, just like cleavage. A good example is
pyrite. However, parting differs from cleavage in some important ways.
 It can not be found in every specimen as is true of cleavage for most
every cleavable mineral.
 It is not absolutely repeatable or reproducible as is cleavage down to
theoretically the very atomic layers that cause cleavage.
 Parting is caused by pressures that are applied to a crystal or by
twinning. The pressure breaks the crystal on a plane of weakness.
Parting
 With pressure parting the actual break formed long before the crystal
was excavated from the ground and may be due to tectonic or
isostatic pressures that have been forced on the crystal.
 Most parting is seen as fracture lines that are incomplete or healed
(the crystal continued to grow and sealed the break) and might
appear as striations or planes of concentrated inclusions.