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