GEMS EXAM 1 QUESTIONS & ANSWERS
gemology - Answer -sub division of mineralogy
gem - Answer -mineral, rock, or organic material that possesses some degree of
beauty, rarities, and durability
beauty - Answer -subjective, depends on the eye of the beholder
*based on color, symmetry, luster, and transparency
durability - Answer -combination of hardness, toughness, and stability
hardness - Answer -what could scratch something else, resistance to scratching
*controlled by bonding
*weakest bond in gem
toughness - Answer -resistance to breaking
*how hard you have to hit something in order for it to break
stability - Answer -chemistry-> light, heat, acid, are ineffective
rarity - Answer -how available something is. dependent on nature and man
value - Answer -very volatile and is set by the market
*if you have a lot, price goes down
*if you dont have enough, price goes up
mineral - Answer -naturally occurring crystalline solid with a definite, homogeneous
chemical composition usually formed by inorganic processes
*made by nature, not in a lab (naturally occurring)
*crystalline-highly ordered internal structure
*definite, homogenous composition
crystalline - Answer -highly ordered internal structure
what does having homogenous composition mean? - Answer -diamond is only carbon
C
*composition stays the same
organic - Answer -made from living things (pearls, ivory, amber)
Inorganic - Answer -(least important because of some exceptions) not a byproduct of
life
how many natural minerals have been found - Answer -5,000
, what are the 3 subtypes of gems - Answer -rocks
mineral
organic
rock - Answer -*groups of crystals
*lapiz lazuli, Jade
mineral - Answer -A solid inorganic substance of natural occurrence.
*groups: quarts, garnite
*Species: composition
*Varieties: color
what does the homogeneous composition of a mineral enable them to do? - Answer -
break down differently
1. durability
2. hardness
3. toughness
4. controlled by bonding
5. concerned with force and stress
strain - Answer -the response of a gem to stress (force)
what are the 3 main ways gemstones break? - Answer -cleavage
parting
fracture
cleavage - Answer -the tendency of a gem to break along parallel of weak bonding
*breaking is determined by weakness
basal - Answer -all breaks go in one direction
intersecting directions (cleavage) - Answer -cubic, octahedral, rhombahedral
different types of quality - Answer -perfect: smooth, reflective surfaces
good: planes, but no "mirror finish"
poor: irregular
parting - Answer -systematic, but irregular breaking that occurs along planes of
structural weakness
*not caused by bonding (defects: strain)
*Corundum (sapphire) and Ruby are the best examples of this
fracture - Answer -breaking along irregular surfaces
*strength of bonds is equal in all directions
*in a faceted gem, all breaks are called a "feather"
gemology - Answer -sub division of mineralogy
gem - Answer -mineral, rock, or organic material that possesses some degree of
beauty, rarities, and durability
beauty - Answer -subjective, depends on the eye of the beholder
*based on color, symmetry, luster, and transparency
durability - Answer -combination of hardness, toughness, and stability
hardness - Answer -what could scratch something else, resistance to scratching
*controlled by bonding
*weakest bond in gem
toughness - Answer -resistance to breaking
*how hard you have to hit something in order for it to break
stability - Answer -chemistry-> light, heat, acid, are ineffective
rarity - Answer -how available something is. dependent on nature and man
value - Answer -very volatile and is set by the market
*if you have a lot, price goes down
*if you dont have enough, price goes up
mineral - Answer -naturally occurring crystalline solid with a definite, homogeneous
chemical composition usually formed by inorganic processes
*made by nature, not in a lab (naturally occurring)
*crystalline-highly ordered internal structure
*definite, homogenous composition
crystalline - Answer -highly ordered internal structure
what does having homogenous composition mean? - Answer -diamond is only carbon
C
*composition stays the same
organic - Answer -made from living things (pearls, ivory, amber)
Inorganic - Answer -(least important because of some exceptions) not a byproduct of
life
how many natural minerals have been found - Answer -5,000
, what are the 3 subtypes of gems - Answer -rocks
mineral
organic
rock - Answer -*groups of crystals
*lapiz lazuli, Jade
mineral - Answer -A solid inorganic substance of natural occurrence.
*groups: quarts, garnite
*Species: composition
*Varieties: color
what does the homogeneous composition of a mineral enable them to do? - Answer -
break down differently
1. durability
2. hardness
3. toughness
4. controlled by bonding
5. concerned with force and stress
strain - Answer -the response of a gem to stress (force)
what are the 3 main ways gemstones break? - Answer -cleavage
parting
fracture
cleavage - Answer -the tendency of a gem to break along parallel of weak bonding
*breaking is determined by weakness
basal - Answer -all breaks go in one direction
intersecting directions (cleavage) - Answer -cubic, octahedral, rhombahedral
different types of quality - Answer -perfect: smooth, reflective surfaces
good: planes, but no "mirror finish"
poor: irregular
parting - Answer -systematic, but irregular breaking that occurs along planes of
structural weakness
*not caused by bonding (defects: strain)
*Corundum (sapphire) and Ruby are the best examples of this
fracture - Answer -breaking along irregular surfaces
*strength of bonds is equal in all directions
*in a faceted gem, all breaks are called a "feather"
