GIA Diamond Essentials Questions and Correct Answers, Exam Prep 2024.

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 feathers collective term for diamond cleavages and fractures cleavage a type of break that is parallel to the weakest direction in the gems structure fracture a break in any direction other than the cleavage direction graining when the crystal grows and it develops irregularities in its atomic structure- looks like faint lines/streaks 5 factors that determine the effect of characteristics on clarity Size (how big are inclusions), number (how many), location (are they in the heart of the stone), relief (contrast between the inclusion and the diamond), nature (type of characteristic) manufacturers person/company that cuts and polishes diamonds and stones (cutters) bruting forming the basic face up outline of a round or rounded shape diamond to prepare it for facetting (aka "rounding up" or "girdling") - 1st step in cutting process bearding small feathers that extend from surface of girdle into stone