GIA Diamond Essentials Questions and Correct
Answers, Exam Prep 2024.
chemical element
consists of only one kind of atom
mineral
inorganic. most minerals are a combo of 2 or more elements
diamonds form
within 90-120 miles below earth's surface
value factos
features used to judge the quality and value of stones - a diamonds value is based on
its combo of the Four C's
inclusions
clarity characteristic totally enclosed in a polished gemstone or extending into it from the
surface. affect value most
blemishes
clarity characteristic on the surface of a gemstone (surface irregularity). includes
scratches and knicks on a surface
rarest diamond colors
red, purple, green, orange- then pink and blue
lab-grown
manmade material with the same chemical composition, crystal structure, and
properties
simulants/imitations
simply look like naturals- not the same composition (can be man made or natural) - cz,
moissanite, glass, zircon, LG spinel
Federal Trade Commission (FTC)
established by congress in 1914 to protect consumers from unlawful business
cut
how light performs in a stone- affects brightness, fire, and scintillation
brightness
effect of stone's internal and external reflections of white light (brilliance)
fire
flashes of color in a diamond
scintillation
flashes of light and contrasting dark areas seen when the diamond, light, or observer
move
crown
top part of diamond- above firdle
girdle
narrow section between crown and pavillion- functions as the setting edge
pavillion
lower part- below girdle
facets
, flat, polished surface
culet
small facet at bottom of stone
brilliant cut
cutting style with triangular or kite shaped facets that radiate from the center toward the
girdle
standard round brilliant
57-58 facets (full cut) - 58th facet is the culet if it has one
single cut
17-18 facets
fancy cuts
any shape other than round brilliant
step cuts
long narrow facets in rows parallel to girdle on both crown and pavillion- usually in 3 or 4
rows
mixed cuts
cut that combines brilliant and step cut styles - usually step facets are on crown and
brilliant on pavillion
branded cuts
style developed, named, and promoted by a specific manufacturer
carat
unit of weight. one carat is 0.2 grams
durability
gemstones ability to withstand wear, heat, and chemicals - 3 properties: hardness,
toughness, stability
hardness
resistance to scratching and abrasion
toughness
resistance to breaking and chipping - diamonds are less tough where the atoms are not
bonded as tightly together
stability
ability to resist chemicals and temperature changes
Moh's scale
ranking of relative hardness of 10 minerals. Established 1822 by Fredrick Mohs.
Mohs scale order 10-1
Diamond, corundum, topaz, quartz, orthoclase feldspar, apatite, fluorite, calcite,
gypsum, talc
cleavage direction
where atoms are farthest apart
thermal shock
damage caused by sudden, extreme temperature changes. diamonds will burn at 1562
degrees F
mining ratio
ratio of diamond to ore when mining is 0.30 carat per metric ton of rock
mining locations
frozen northern canada, western australia, bottom of atlantic, desert of south africa
Answers, Exam Prep 2024.
chemical element
consists of only one kind of atom
mineral
inorganic. most minerals are a combo of 2 or more elements
diamonds form
within 90-120 miles below earth's surface
value factos
features used to judge the quality and value of stones - a diamonds value is based on
its combo of the Four C's
inclusions
clarity characteristic totally enclosed in a polished gemstone or extending into it from the
surface. affect value most
blemishes
clarity characteristic on the surface of a gemstone (surface irregularity). includes
scratches and knicks on a surface
rarest diamond colors
red, purple, green, orange- then pink and blue
lab-grown
manmade material with the same chemical composition, crystal structure, and
properties
simulants/imitations
simply look like naturals- not the same composition (can be man made or natural) - cz,
moissanite, glass, zircon, LG spinel
Federal Trade Commission (FTC)
established by congress in 1914 to protect consumers from unlawful business
cut
how light performs in a stone- affects brightness, fire, and scintillation
brightness
effect of stone's internal and external reflections of white light (brilliance)
fire
flashes of color in a diamond
scintillation
flashes of light and contrasting dark areas seen when the diamond, light, or observer
move
crown
top part of diamond- above firdle
girdle
narrow section between crown and pavillion- functions as the setting edge
pavillion
lower part- below girdle
facets
, flat, polished surface
culet
small facet at bottom of stone
brilliant cut
cutting style with triangular or kite shaped facets that radiate from the center toward the
girdle
standard round brilliant
57-58 facets (full cut) - 58th facet is the culet if it has one
single cut
17-18 facets
fancy cuts
any shape other than round brilliant
step cuts
long narrow facets in rows parallel to girdle on both crown and pavillion- usually in 3 or 4
rows
mixed cuts
cut that combines brilliant and step cut styles - usually step facets are on crown and
brilliant on pavillion
branded cuts
style developed, named, and promoted by a specific manufacturer
carat
unit of weight. one carat is 0.2 grams
durability
gemstones ability to withstand wear, heat, and chemicals - 3 properties: hardness,
toughness, stability
hardness
resistance to scratching and abrasion
toughness
resistance to breaking and chipping - diamonds are less tough where the atoms are not
bonded as tightly together
stability
ability to resist chemicals and temperature changes
Moh's scale
ranking of relative hardness of 10 minerals. Established 1822 by Fredrick Mohs.
Mohs scale order 10-1
Diamond, corundum, topaz, quartz, orthoclase feldspar, apatite, fluorite, calcite,
gypsum, talc
cleavage direction
where atoms are farthest apart
thermal shock
damage caused by sudden, extreme temperature changes. diamonds will burn at 1562
degrees F
mining ratio
ratio of diamond to ore when mining is 0.30 carat per metric ton of rock
mining locations
frozen northern canada, western australia, bottom of atlantic, desert of south africa
