Definition 1 of 48
An aggregate made up of individual crystals detectable only under very high magnification.
fracture
crystallographic
cryptocrystalline
topaz
Definition 2 of 48
Many fashioned rubies have shallow proportions because they are cut from...
flat crystals
tall, columnar crystals
flattened cleavage pieces
crystalline minerals
Definition 3 of 48
Any break in a gem other than cleavage or parting.
hardness
cleavage
fracture
density
,Definition 4 of 48
Small pocket in a gem that's filled with fluids and, sometimes, gas bubbles and tiny crystals.
Usually created by environmental changes during crystal growth.
three-phase inclusion
aggregate
stability
liquid inclusion
Definition 5 of 48
How well a gemstone resists breaking and chipping.
stability
durability
hardness
toughness
Definition 6 of 48
A hollow cavity in a gem, usually filled with a liquid and a gas.
two-phase inclusion
negative crystal.
thin film
liquid inclusion
Definition 7 of 48
Which type of twinning looks as if two crystal halves are mirror images?
polysynthetic
contact
regional
inclusions
,Definition 8 of 48
Which gems are cryptocrystalline aggregates?
chalcedony and turquoise
nephrite and jadeite
iron and titanium
opal and amethyst
Definition 9 of 48
A unit cell defines a mineral's...
three-phase inclusion
basic identity
habit
shape.
Definition 10 of 48
What do you call gems that require rare chemical elements or unique geological conditions, or
both, to form?
rare
common
fracture
small
, Definition 11 of 48
A flat break in a gemstone caused by concentrated included minerals parallel to a twinning
plane.
fracture
hardness
parting
cleavage
Definition 12 of 48
A characteristic enclosed within a gemstone, or reaching its surface from the interior.
correlation
parting
intrusion
inclusion
Definition 13 of 48
How well a gemstone resists scratches. Usually expressed in terms of the Mohs scale, with
diamond the hardest (10) and talc the softest (1).
hardness
durability
density
fracture
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