October 1996 Gem Quiz

1. Oligoclase is known to exhibit which of the following phenomenas?
   Play of color
   Iridescence
   Girasol
   Adularescence

2. Refractometer testing for the optic sign of the gemstone pearl may yield which of the following results?
   Uniaxial positive
   Uniaxial negative
   Biaxial positive
   Biaxial negative

3. Nephrite is found commonly in which of the following transparency classifications?
   Opaque
   Semi-transparent
   Semi-transluscent
   All except semi-transparent

4. Granular fracture characteristics can be exhibited by which of the following gemstones?
   Sodalite
   Zircon
   Grossularite
   Almandine

5. Synthetic spinel verneuil is known to exhibit which of the following phenomenas?
   Color change
   Girasol
   None of these answers
   Labradorescence

6. Spodumene is known to exhibit which of the following streak plate responses?
   Pale red
   White
   Yellowish brown
   Dull black

7. Opal is found commonly in which of the following transparency classifications?
   Opaque
   Semi-transparent
   There is no single best answer
   Semi-transluscent

8. The Moh's hardness of turquoise can be?
   5.300
   6.000
   There is no single best answer
   5.700

9. The refractometer, when used properly with a monochromatic sodium light source, may yield a birefringence value for plastic of?
   0.010
   0.001
   0.024
   None of the above

10. Which of the following gemstones exhibits a characteristic strong band at 504 nanometers?
    Topaz.
    Chrysoberyl
    Cordierite
    Almandine

11. A refractometer, when used properly with a monochromatic sodium light source, may yield a refractive index value for the isotropic gemstone rhodolite of?
    1.750
    1.721
    1.725
    1.731

12. Peridot commonly can exhibit which of the following lusters?
    Waxy
    Silky
    None of these
    Pearly

13. The refractometer, when used properly with a monochronomatic sodium light source, may yield a birefringence value for corundum of?
    0.010
    0.007
    0.011
    0.006

14. Rhodolite can crystalize in which of the following crystal systems?
    Hexagonal
    Triclinic
    None of these
    Monoclinic

15. Orthoclase is known to exhibit which of the following streak plate responses?
    Black
    Dark green
    Colorless

16. Olivine should always sink in which of the following specific gravity fluids?
    2.67
    All of these
    3.05
    2.62

17. Calcareous coral is known to exhibit which of the following responses to short wave ultra violet excitation?
    Brown/tan
    Red/pink
    Blue
    Orange

18. Which of the following gemstones exhibits a characteristic strong line at 535 nanometers?
    Grossularite
    Rhodocrosite
    Perodot
    Andalusite

19. Lapis Lazuli commonly can exhibit which of the following fracture characteristics?
    Sub-chonchoidal
    Step-like
    Even
    Splintery

20. Refractometer testing for the optic sign of the gemstone chrysoberyl may yield which of the following results?
    Uniaxial
    Uniaxial positive
    Uniaxial negative
    Biaxial positive

GemData will continue to have a future Gem Quiz each month. Would you like to see your questions used for a future Gem Quiz? GemData will be happy to post the persons name who submitted the question if so desired. Please submit your questions on any subject to do with the Gem, Diamond or Jewelry Industry with the answers to Lance Kanaby at lkanaby@buffnet.net