Day 2: Correlation Course Exam Flashcards
The crystal habit is:
the general aspect or shape a crystal possesses
how are crsytal forms related to each other?
by the symmetry the crystal possesses
what defines whether a substance is crystalline?
the internal atomic structure
crystals are bounded by:
smooth surfaces
under what conditions do well-developed crystals form?
suitable physicochemical conditions
a perfect crystal is
a crystal with both external form and internal atomic structure
it is used to denote the general shapes of crystals
habit
what is the defining characteristic of naturally occuring crystal?
regular geometric form and internal atomic structure
what is the subject matter of crystallography?
external shape, internal structure, and laws governing crystal growth
what did Sir W.H. Bragg and Sir W.L Bragg analyze in 1913, which contributed to the science of crystallography?
crystals of sodium chloride
what phenomenon occurs when a beam of X-ray falls on a crystal and ‘scatters’ in certain directions?
diffraction
the flat surfaces by which crystals are bounded are called:
faces
what is the phenomena where individual scattered wavelets may recombine in phase to produce a diffracted beam?
interference
what is a zone?
set of faces whose mutual intersection gives rise to parallel edges
what is the relationship between faces, solid angles, and edges in a crystal?
f + c = e + 2
the steno’s law of constant angles is also called?
the first law of crystallography
when steno studied quartz crystals, what did he observed of the relationship between adjoining faces?
they were always 120 degrees
which mineral is an example of idiochromatic mineral?
a. quartz
b. beryl
c. garnet
d. tourmaline
c. garnet
why is colour not a reliable property for identifying most minerals?
it varies for most minerals
quartz may appear as pale brown (smoky) or pale pink (rose quartz). this is due to:
presence of trace elements
when a mineral absorbs all light and reflects none:
it appears black
these are minerals that have characteristic color related to their composition.
idiochromatic
which element is responsible for the green color in minerals?
Fe^2+
diamond and graphite have different physical properties. the differences in their physical properties is due to the:
bonding between atoms
why is color considered an unreliable property for identifying minerals?
it varies due to different factors
the limit hardness in which beyond you cannot use a streak plate to determine a mineral’s streak is:
7
which mineral has a white streak despite having different colors?
a. fluorite
b. hematite
c. galena
d. pyrite
a. fluorite
a black hematite gives what streak color?
reddish brown
why do metallic minerals generally have dark colored streaks?
they absorb most of the light
what makes streak a useful property for identifying metallic minerals?
it is generally constant or similar for all varieties
which physical property of minerals is related to their weight compared to the weight of an equal volume of water?
specific gravity
how many minerals are known to exist in the Earth’s crust according to the International Mineralogical Association?
6,000
which mineral is commonly used in toothpaste?
a. quartz
b. halite
c. calcite
d. gypsum
c. calcite
cleavage refers to:
the way a mineral breaks along planes of weakness
it is the ability of a mineral to emit light when exposed to certain conditions
luminescence
which of the following is NOT a property used to group physical propertoes of minerals?
a. hardness
b. color
c. taste
d.fracture
c. taste
which of the following is NOT a property used to identify minerals based on their physical characteristics?
a. lustre
b. chemical composition
c. hardness
d. transparence
b. chemical composition
the resistance of a mineral to being scratched is its:
hardness
why does a mineral appear green to our eyes?
it reflects green wavelength and absorbs others
it describes a confused aggregate of imperfect crystal grains interfering with each other during growth
crystalline?
crystals that have no developed faces are called:
anhedral crystals
under what conditions do minerals grow into a definite crystal form?
favourable environmental conditions
how is cleavage defined based on ease in obtaining?
excellent, good, imperfect
basal cleavage refer to:
surface parallel to the base of the crystal
which type of luminescence continues even after the existing rays are cut off?
Phosphorescent
what type of luster do minerals like steel, gold, and silver exhibit?
metallic luster
the degree of transparency of a mineral is its
diaphaneity
it is the emission of light by a mineral that is not the result of heating?
luminescence
this describes minerals that appear foggy due to light diffusion and internal absorption.
translucent
what type of minerals emit light during exposure to UV light, x-rays, or cathode rays?
fluorescent
cryptocrystalline means:
minerals with traces of crystalline structure
luster that is similar to that of polished glass
vitreous
this type of luster is often seen in minerals like sphalerite, opal, and amber
resinous
a mineral described as having a milky shimmer resemblinh an iridescent pearl is called:
silky
minerals like asbestos, serpentine, and malachite exhibit which type of luster that gives a silk or satin-like appearance?
silky
habit described as having many hair-like or thread like filaments or a twisted wire, as seen in native copper and silver
filiform
described as having fibers radiating from a center, producing a star-like shape, as in wavellite
stellate
luster described as having a high refractive index
adamantine
this habit is described as small spheroids or ellipsoids resembling tiny fish eggs
oolitic
this resembles tree branches or a river system
dendritic
which crystal habit is spherical aggregation, like a bunch of grapes
botryoidal
what crystal habit resembles a network of small crystals developed in a cross mesh pattern?
reticulated
it resembles a lump of sugar and is evenly sized
granular
galena, garnet, and pyrite all belongs to what crystal system?
cubic
the following minerals are tetragonal, except:
a. rutile
b. cassiterite
c. zircon
d. beryl
d. beryl
hexagonal
apatite is to hexagonal as tourmaline is to:
trigonal
to which crystal system do minerals like sulphur, barite, and olivine belong?
orthorhombic
list of monoclinic minerals?
gypsum, augite, hornblende
in which crystal system does topaz belong?
orthorhombic
how many directions does prismatic cleavage have?
two
which mineral shows a significant difference in hardness between different scratch directions, with a hardness of 5 parallel to the length and 7 across the lenght?
kyanite
which mineral is known for its high specific gravity and is heavy due to its metallic luster?
galena
the property of mineral which refers to the resistance it offers when subjected to crushing, bending, breaking, or tearing.
tenacity
what taste is associated with sylvite?
bitter
who suggested a scale of fusibility for minerals?
Kobell
what are striations in minerals?
hairline grooves on cleavage planes or crystal faces
how can you differentiate between cleavage planes and fracture surfaces?
cleavage planes are smooth and flat, while fracture surfaces are generally rough or uneven
which minerals commonly exhibit striations on their cleavage planes or crystal faces?
quartz and feldspar
what is the hardness of talc on the Moh’s scale?
1
which common object can be used to test if a mineral is a soft mineral?
glass plate
what is considered the most valued property for gems?
clarity
what is the term for minerals that develop an electrical charge when subjected to stress?
Piezoelectric
Geiger-Muller counters are used to measure:
radioactivity
the four C’s in the assessment of gemstones are:
Color, Cut, Clarity, Carat
what property of gemstones refers to the absence of internal flaws or inclusions?
clarity
what brings a wide range of colours in gems?
presence of trace elements
which type of gems are prized for their vivid colours even if they are opaque?
jade
what is the basis of a standard weight called carat?
a fifth of a gram
which minerals are drawn to a magnetic field as along as the magnetic field is present?
paramagnetic
in reconstructing geological history, what do magnetic minerals help in recording?
direction of earth’s magnetic field through time
how are ore minerals separated from waste materials?
utilization of magnetic property
which type of minerals have no attraction for a magnetic field?
diamagnetic
which carbonate minerals show effervescence in hot hydrochloric acid?
dolomite and rodochrosite
what distinguishes gemstones from other minerals?
their beauty
which of the following is NOT considered one of the rarest and most valuable gems?
turquoise
which gemstones are composed of Al2O3?
ruby and sapphire
which gemstone is made of chalcedony?
Opal
which gemstone is known as green beryl
Emerald
who proposed a chemical composition based mineral classification system in 1854?
J.D. Dana
what did Lawrence Bragg’s discovery of X-rays enable in mineral classification?
determining atomic arrangement
how many main mineral groups are minerals classified into in the Dana system?
8
