GIA COLORED STONES COMPREHENSIVE
STUDY GUIDE 2026 GEM IDENTIFICATION
CONCEPTS SOLUTIONS VERIFIED A+
◉ gemology
Answer: the study of gems
◉ organic
Answer: once living, or produced by a living organism (plant or
animal)
◉ minerals
Answer: a natural, inorganic substance with a characteristic
chemical composition and usually characteristic structure
◉ inorganic
Answer: composed of, or arising from, non-living matter
◉ chemical compositions
Answer: types and relative quantities of atoms that make up a
material
,◉ durability
Answer: a gemstone's ability to withstand wear, heat, and chemicals
◉ luster
Answer: the appearance of a material's surface in reflected light
◉ transparency
Answer: degree to which a material allows light to pass through it
◉ hardness
Answer: how well a gemstone resists scratches and abrasion
◉ toughness
Answer: how well a gemstone resists breaking, chipping, and
cracking
◉ stability
Answer: how well a gemstone resists the effects of light, heat, and
chemicals
◉ crystal structure
,Answer: regular, repeating internal arrangement of atoms in a
material
◉ chemical formula
Answer: written description of a material's chemical makeup
◉ trace elements
Answer: atoms in a gem that aren't part of its essential chemical
composition
◉ amorphous
Answer: lacking a regular crystal structure
◉ species
Answer: a broad gem category based on chemical composition and
crystal structure
◉ variety
Answer: a subcategory of species based on color, transparency, or
phenomenon
◉ phenomenon
Answer: an unusual optical effect displayed by a gem
, ◉ groups
Answer: a family of gems from several closely related mineral
species
◉ natural gems
Answer: gems produced by natural processes, without human help
◉ lab-grown gem
Answer: a manmade (synthetic) gem with essentially the same
chemical composition, crystal structure, and properties as its natural
counterpart
◉ Federal Trade Commission
Answer: a US government agency that issues guidelines for the
jewelry trade
◉ by color alone
Answer: How were gems once classified by?
◉ minerals
Answer: What are most gems?
STUDY GUIDE 2026 GEM IDENTIFICATION
CONCEPTS SOLUTIONS VERIFIED A+
◉ gemology
Answer: the study of gems
◉ organic
Answer: once living, or produced by a living organism (plant or
animal)
◉ minerals
Answer: a natural, inorganic substance with a characteristic
chemical composition and usually characteristic structure
◉ inorganic
Answer: composed of, or arising from, non-living matter
◉ chemical compositions
Answer: types and relative quantities of atoms that make up a
material
,◉ durability
Answer: a gemstone's ability to withstand wear, heat, and chemicals
◉ luster
Answer: the appearance of a material's surface in reflected light
◉ transparency
Answer: degree to which a material allows light to pass through it
◉ hardness
Answer: how well a gemstone resists scratches and abrasion
◉ toughness
Answer: how well a gemstone resists breaking, chipping, and
cracking
◉ stability
Answer: how well a gemstone resists the effects of light, heat, and
chemicals
◉ crystal structure
,Answer: regular, repeating internal arrangement of atoms in a
material
◉ chemical formula
Answer: written description of a material's chemical makeup
◉ trace elements
Answer: atoms in a gem that aren't part of its essential chemical
composition
◉ amorphous
Answer: lacking a regular crystal structure
◉ species
Answer: a broad gem category based on chemical composition and
crystal structure
◉ variety
Answer: a subcategory of species based on color, transparency, or
phenomenon
◉ phenomenon
Answer: an unusual optical effect displayed by a gem
, ◉ groups
Answer: a family of gems from several closely related mineral
species
◉ natural gems
Answer: gems produced by natural processes, without human help
◉ lab-grown gem
Answer: a manmade (synthetic) gem with essentially the same
chemical composition, crystal structure, and properties as its natural
counterpart
◉ Federal Trade Commission
Answer: a US government agency that issues guidelines for the
jewelry trade
◉ by color alone
Answer: How were gems once classified by?
◉ minerals
Answer: What are most gems?
