crystalline minerals️️what are classified into seven crystal systems, depending on the
symmetry of their unit cells?
exterior shape️️what part of a crystal often indicates its symmetry at an atomic level?
rare️️What do you call gems that require rare chemical elements or unique geolo...
GIA Colored Stones Assignment 3 with comprehensive questions
and answers 2024/2025
crystalline minerals✔️✔️what are classified into seven crystal systems, depending on the
symmetry of their unit cells?
exterior shape✔️✔️what part of a crystal often indicates its symmetry at an atomic level?
rare✔️✔️What do you call gems that require rare chemical elements or unique geological
conditions, or both, to form?
twinning✔️✔️What can result form a change during crystal growth, or from cooling or pressure
after the crystal has grown?
inclusions✔️✔️What can help identify a colored stone as natural or manmade, untreated or
treated?
large inclusions✔️✔️What can dramatically affect beauty, value, and durability?
identify them✔️✔️What can a gemstone's recognizable crystal shape help do?
finished stones✔️✔️The shapes and sizes of rough gem crystals affect the shapes and sizes of...
gem density and specific gravity✔️✔️What two things depend on the types of atoms a gem is
made of, and how closely they're packed together?
cleavage, parting, and fracture✔️✔️The three different ways a gem breaks are called...
reaction to external stress✔️✔️A gem's crystal structure determines its...
, aggregate✔️✔️A mass of tiny, randomly oriented crystals.
cleavage✔️✔️A smooth, flat break in a gemstone parallel to planes of atomic weakness, caused by
weak or fewer bonds between atoms, or both.
conchoidal fracture✔️✔️A curved and ridged fracture in a gemstone, extending from the surface
inward.
cryptocrystalline✔️✔️An aggregate made up of individual crystals detectable only under very high
magnification.
density✔️✔️How heavy an object is in relation to its size.
durability✔️✔️A gemstone's ability to withstand wear, heat, and chemicals.
fracture✔️✔️Any break in a gem other than cleavage or parting.
habit✔️✔️The characteristic external crystal shape or form of a mineral.
hardness✔️✔️How well a gemstone resists scratches. Usually expressed in terms of the Mohs
scale, with diamond the hardest (10) and talc the softest (1).
inclusion✔️✔️A characteristic enclosed within a gemstone, or reaching its surface from the
interior.
liquid inclusion✔️✔️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.
microcrystalline✔️✔️An aggregate made up of individual crystals visible under magnification.
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