Geology minerals
finger nail hardness
2.5
steel nail hardness
5.0
glass plate hardness
5.5
Cleavage
the tendency of a mineral to split consistently along certain planes where the atoms are weakly bonded.
Fracture
– no definite planes of weakness in the bonding of the atoms so the mineral just breaks along irregular surfaces.
CONCHOIDAL fracture –
irregular breakage, surfaces are somewhat curved (like the way glass breaks)
Quartz is noted for its conchoidal fracture
Quartz is noted for its conchoidal fracture
HACKLY fracture
fracture – breakage surfaces are jagged (such as the mineral copper)
UNEVEN fracture
– some minerals break apart in no distinguishable pattern.
Lodestone
acts
like a natural magnet
like a natural magnet
Effervescence –
bubbly reaction in HCl, “fizzing” (calcite)
Piezoelectricity –
emits an electric current when put under pressure (quartz)
Double-refraction
– the
doubling of images when
light passes through
mineral (calcite)
doubling of images when
light passes through
mineral (calcite)
Fluorescence-
mineral (calcite, fluorite) glow when subjected to ultraviolet (black) light
Labradorescence
– the
colorful hue seen at
certain angles while
the mineral labradorite
reflects light
colorful hue seen at
certain angles while
the mineral labradorite
reflects light
a series
of very fine parallel
scratches found on
the cleavage surfaces
of some minerals
(labradorite)
of very fine parallel
scratches found on
the cleavage surfaces
of some minerals
(labradorite)
Striations –
. Van der Waals
weak attraction between chains or sheets of atoms
covalent
atoms share electrons
. ionic:
atoms attracted by opposite charges imparted by gain or loss of electrons.