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To enter the 2001 Challenge, you must mark your answers on the response card provided in the Spring 2001 issue. Click here to order a copy of this issue. Entries are due no later than August 6, 2001. All entries will be acknowledged with a letter and an answer key after the due date; the correct answers also will be posted on this Web page.
Score 75% or better, and you will receive a GIA Continuing Education Certificate. If you are a member of the GIA Alumni Association, you will earn five Carat Points toward GIA's Alumni Circle of Achievement. Earn a perfect score, and your name will also be featured in the Fall 2001 issue of Gems & Gemology.
The following 25 questions are based on information from the four 2000 issues of Gems & Gemology.
1. What diamond type can be changed from brown to greenish yellow by HPHT processing?
A. Type IIa
B. Type IIb
C. Type Ia
D. Type Ib
2. The most common type of treatment (aside from dyeing) used for gems continues to be
A. irradiation.
B. heat treatment.
C. diffusion treatment.
D. fracture filling.
3. Which of these analytical techniques could not be considered “mature” to gemologists in the 1990s?
A. Isotopic studies
B. Ultraviolet-visible spectroscopy
C. Electron microprobe analysis
D. X-ray fluorescence spectrometry
4. If bead-nucleated Chinese freshwater cultured pearls do become common in the future, their nature will be readily identifiable by
A. Fourier-transform infrared spectroscopy.
B. magnification.
C. X-radiography.
D. X-ray diffraction.
5. Most of the corundum mined from the Jegdalek deposit in east-central Afghanistan is
A. ruby.
B. pink sapphire.
C. blue sapphire.
D. bicolored blue and red-to-pink corundum.
6. The emphasis on fancy-color diamonds in jewelry during the 1990s was primarily due to the greater availability of fancy brown, yellow, and pink diamonds from
A. Australia.
B. Canada.
C. Brazil.
D. Russia.
7. The larger size of Chinese freshwater cultured pearls over the last several years can be attributed primarily to
A. a longer cultivation period and the use of younger mussels.
B. the change from the Hyriopsis cumingi mussel to the Cristaria plicata.
C. the use of mantle-tissue nuclei.
D. the use of reject cultured pearls as nuclei.
8. In Myanmar’s Jade Tract, miners often can identify the occasional jadeite boulder by
A. its slightly sticky feel.
B. the distinct ringing sound it makes when struck with a metal tool.
C. its greater heft than other types of rock in the conglomerate.
D. all of the above.
9. Spectral features due to single substitutional nitrogen atoms in a nominally type IIa diamond provide an indication of
A. fracture filling.
B. HPHT treatment.
C. irradiation.
D. a surface coating.
10. The purple to purplish red color of chromium-bearing taaffeites is a function of the relative amounts of chromium and _______ present.
A. cobalt
B. titanium
C. iron
D. manganese
11. A new laser treatment for diamonds, which typically does not have a surface-reaching drill hole, works best on
A. small inclusions.
B. inclusions deep within a stone.
C. dark inclusions near the surface.
D. light inclusions far from the stone’s surface.
12. Diagnostic inclusions, in the form of ______, were documented in Tairus hydrothermal synthetic emeralds in the 1990s.
A. iron oxides
B. platinum platelets
C. flux “fingerprints”
D. chromite
13. Evidence that a near-colorless type IIa diamond has been HPHT treated can be provided by a combination of
A. photoluminescence spectra and inclusions.
B. graining and cathodoluminescence.
C. X-ray topography and infrared spectra.
D. infrared spectra and graining.
14. The most significant amethyst-producing country of the 1990s was
A. Zambia.
B. Uruguay.
C. Brazil.
D. Canada.
15. Diamonds filled with Oved’s new XL-21 glass formulation are characterized by
A. a strong flash effect.
B. the “Oved” logo inscribed on a bezel facet.
C. the detection of Pb and Bi by EDXRF analysis.
D. all of the above.
16. Which imitation rough was most common in the 1990s?
A. Imitation diamond crystals
B. Imitation ruby crystals
C. Imitation sapphire crystals
D. Imitation emerald crystals
17. Which significant technological challenge of the 1980s remained in the 1990s?
A. Identifying synthetic diamonds by their fluorescence
B. Determining origin of color for green diamonds
C. Identifying GE POL diamonds
D. Characterizing diamond fillers
18. HPHT-treated greenish yellow to yellowish green diamonds may show
A. chalky greenish yellow fluorescence.
B. strong green “transmission” (luminescence to visible light).
C. fractures with etched, frosted textures or partial graphitization.
D. all of the above.
19. Most of the shell jewelry discovered at archeological sites on the island of Antigua was manufactured from the ______ shell.
A. queen conch
B. nautilus
C. abalone
D. thorny oyster
20. The ______ effect of one gem material overlaid on another was introduced to the jewelry world in the 1990s.
A. “optic dish”
B. “drusy”
C. “Mystère”
D. “trompe l’oeil”
21. Gem-quality haüyne is rarely seen in jewelry because of
A. its high specific gravity and low luster.
B. its rarity and low hardness.
C. its treatment with paraffin wax.
D. its popularity as a collector’s stone.
22. X-ray diffraction analysis identified lazurite and _______ as the principal minerals in samples of first-grade lapis lazuli from both Chile and Afghanistan.
A. wollastonite
B. barite
C. pyrite
D. calcite
23. The first major demantoid garnet locality outside of Russia was discovered in _______ in the mid-1990s.
A. Namibia
B. Tanzania
C. China
D. Madagascar
24. The most important factor in the evaluation of Burmese jadeite is
A. diaphaneity.
B. texture.
C. color.
D. cut.
25. Sapphires from the Antsiranana Province of Madagascar show internal features typical of ______ deposits.
A. marble-hosted
B. metamorphic
C. basaltic-magmatic
D. alluvial
Remember, to enter the 2001 Challenge you must mark your answers on the response card provided in the Spring 2001 issue.
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