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103 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Cultured pearl with a hole drilled all the way through; sometimes called drilled-through. |
Full-drilled
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4 |
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...helps prospectors pick the right places to look for gems. |
An understanding of gemstone formation
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18 |
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Light that exits through the pavilion in an uncontrolled way due to compromises in a gem’s proportions.
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Unplanned light leakage
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32 |
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Hues with ... usually don’t reach the same high levels of saturation as those with medium tone.
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very light or very dark tone
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46
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The earth’s innermost layer.
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Core
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60
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Workable alluvial deposit of gem minerals with economic potential.
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Placer
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74
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Treasured for thousands of years, jade has great cultural significance, especially in…
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Asia
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88
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Nephrite is an excellent, ... alternative to jadeite.
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readily available, lower-priced
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102
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The first impression of an object’s basic color.
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Hue
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116
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... is an adaptation of the natural pearl formation process.
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Pearl culturing
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130
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The characteristic external crystal shape or form of a mineral.
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Habit
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144
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Change in a gem’s crystal direction during or after growth.
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Twinning
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158
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A gem’s recorded .(2).. can help identify it later.
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carat weight and dimensions
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172
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Each value factor ... for different pearl types.
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varies in importance
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186
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A smoothly rounded polished gem with a domed top and a flat or curved base.
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Cabochon
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200
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Lower part of a faceted gem below the girdle.
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Pavilion
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214
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... is done by highly skilled workers because it has the greatest impact on a finished gem’s value.
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Preforming
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228
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Topaz is commonly ... but treatment can produce a blue color.
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colorless,
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242
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A grooved, neutrally colored, non-reflective tray, used to match sets of stones.
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Matching tray
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256
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An opening that extends into a gem from the surface.
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Cavity
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270
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... is made of billions of uniform, submicroscopic silica spheres, stacked in an orderly pattern.
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Precious opal
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284
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The preferred level of ... depends on the background color of the opal.
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transparency
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298
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corundum, quartz, tourmaline
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trigonal (rhombohedral) (3)
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312
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toughness of tourmaline
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fair toughness
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326
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4 gems colored by iron and titanium
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blue sapphire, blue spinela, kyanite, tourmaline
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340
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Spots of color near the surface of a jadeite boulder, where the skin is thin enough to allow color to show through.
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Show points
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354
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A gem’s ... determines its reaction to external stress.
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crystal structure
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368
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Contrast between an inclusion and its host gem.
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Relief
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382
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... is the world’s major source of commercial-quality amethyst.
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Brazil
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396
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Color range - lapis
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deep violet blue and royal blue to light blue to greenish blue
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410
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What stone is a porous, semitranslucent to opaque compount of hydrated copper and aluminum phosphate>
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turquoise
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424
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A bead used as the core of a cultured pearl, usually made from a freshwater mussel shell.
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Bead nucleus
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438
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A nacreous, organic gem formed in the body of a mollusk.
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Pearl
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452
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gem - trade term "pink marble"
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Rhodonite
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466
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color range - ruby
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Orangy Red to Purple Red
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480
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Host rock Thai rubies
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basalt
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494
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When and by whom was ruby synthetized?
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1800s by Auguest Verneuil
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508
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Describe blue sapphire mining in Montana
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Montana - pale in color; all but Yogo Gulch are alluvial
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522
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Describe an Australian blue sapphire
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Australian - can be greenish; greenish blue pleochroism; inky
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536
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A treatment that adds color or affects color by deepening it, making it more even, or changing it.
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Dyeing
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550
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Any human-controlled process, beyond cutting and polishing, that improves the appearance, durability, or value of a gem.
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Treatment
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564
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Types of synethetic alexandrite (3)
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Czochralski; Floating zone; Flux; 1987 Kyocera made syntethic cat's eye color-change alexandrite
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578
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Cutting standards are generally looser for …
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low-end goods
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592
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What is the "crosspiece" greek chiasma stone?
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Chiastolite
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606
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What element is necessary for topaz to become pink?
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chromium
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620
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Color range - sherry topaz
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orange to yellow and brown topaz
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634
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two treatments for helidor
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heat treatment (some don't work; some turn aquamarine color); finest left untreated; irradiated
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648
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Produced by, or derived from, a living organism.
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Organic
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662
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crystal type of aquamarine
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typically six-sided columns with flat faces at their ends
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676
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How old is opal?
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formed 150-30 mil ago;
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690
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Primary mining fire opal
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Mexico
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704
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What are the 6 evaluation factors for opal?
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Six Evaluation Factors - Type of opal, Dominant phenomenal colors, Color pattern, Transparency, Negatives, Symmetry
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718
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What kind of feldspar is andesine?
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calcium/sodium feldspar
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732
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What is the crystal structure of moonstone?
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monoclinic crystal structure
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746
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Treatment for sunstones
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not treated
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760
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The typical corundum color change is from …
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blue or violet in daylight to violetish purple to strongly reddish purple in incandescent light
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774
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mining (4) for kunzite
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Afghanistan, Brazil, Madagascar, California
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788
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In many gemstone varieties, ... are more valued than mixed hues.
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pure hues
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802
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Many gemstone species share some of the same (2) ranges
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hue and saturation
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816
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Describe dravite tourmaline.
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dravite - rich in sodium, magnesium and aluminum; metamorphosed limestone
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830
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color range for paraiba?
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vibrant green to blue or violate
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844
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two treatments for pink and red tourmaline?
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strong pink gems often irradiated near colorless or pale pink, yellow or brown material; indetectable; low temp heat treatment can remove brownish tint
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858
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ideal color peridot
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green without any yellow or brown
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872
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color element orange and purple spinel
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iron and chromium
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886
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when was tsavorite discovered?
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1960s
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900
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Bands of light in certain gems, caused by reflection of light from many parallel, needle-like inclusions or hollow tubes.
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Chatoyancy
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914
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An unusual optical effect displayed by a gem.
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Phenomenon
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928
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what kind of gem is almandite?
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garnet
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942
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color range uvarovite
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green garnet
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956
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Because Italy is the most important ... many coral color terms are Italian.
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coral-marketing center,
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970
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garnet with higher dispersion than diamond
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higher dispersion than diamond
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984
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what kind of garnet is tapazolite?
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pure yellow andradite
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998
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A tiny crystal used as a template to control the size, speed, or direction of growth and the shape of a growing synthetic crystal.
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Seed crystal
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1012
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three quality judgement factors for jadeite
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Color, Transparency, Texture; uniformity of color, minimal mottling
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1026
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how old can amber be?
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120 million
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1040
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4 imitations for calcareous coral
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one of most imitated organic gems; glass; porcelain; various plastics; Gilson imitation coral - clues: beads of coral will not be identical; lines in mold
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1054
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imitation of ammonite?
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none
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1068
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High clarity and lack of treatment make ... an effective emerald alternative.
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chrome diopside
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1082
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transparency for fluorite
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transparent to translucent stone
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1096
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... causes turquoise to appear greenish blue, while copper creates the more desirable pure blue color.
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Iron
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1110
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color of moldovite
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medium to dark yellowish to grayish green
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1124
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4 elements of beryl
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beryllium, aluminum, silicon, oxygen
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1138
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black |
black |
1152
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where is most processing done for pearls? |
Most processing doen in Japan and China |
1166
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Many garnets are ... of two or more garnet species.
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mixtures
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1180
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... has been the most important source of rhodolite since the 1960s.
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East Africa
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1194
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A document that indicates a stone’s geographic origin, based on its inclusions and trace element chemistry.
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Certificate of origin
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1208
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The geographical place where a gem was mined.
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Origin
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1222
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... causes a greater variety of gem colors than any other transition element.
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Iron
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1236
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(2) characteristics can help trained observers separate natural from synthetic gems.
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Internal and external
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1250
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... is one of the oldest gem treatments.
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Dyeing
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1264
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... supplies the majority of commercial-quality rubies.
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Mong Hsu, Myanmar, |
1278
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Most fine sapphires over 100 cts. Are from …
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Sri Lanka |
1292
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The great majority of emeralds contain ... so untreated stones command premium prices.
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filled fractures,
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1306
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... is the only commercial source of gem-quality tanzanite. |
Tanzania
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1320
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Because it withstands rough wear and is subtly colored, cat’seye is traditionally marketed as a …
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man’s gem
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1334
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Colorless zircon’s ... easily distinguishes it from diamond and synthetic cubic zirconia.
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strong double refraction
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1348
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When were first freshwater pearls marketed
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1914
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1362
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Where and when were south sea pearls introduced?
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Western Australia; 1950s
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1376
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Describe quality of Zambian/African amethyst
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Africa - small quantities of best; Zambia (super richly saturated color);
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1390
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two effects of heat treatment on smoky quartz
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heat treatment turns it to "lemon quartz"; can also lighten very dark smoky quartz |
1404
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what is the gem version of quartzite?
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aventurine |
1418
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growth habit chalcedony
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botryoidal |
1432
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