February 1997 Gem Quiz

1. Opal should always sink in which of the following specific gravity fluids?
   3.32
   None of these
   3.05
   2.67

2. When carefully tested with a dichroscope the triclinic gemstone labradorite can show which of the following responses?
   Moderate dichroic
   Weak trichroic
   All of these
   Weak dichroic

3. The Moh's hardness of turquoise can be?
   4.90
   5.50
   6.30
   7.00

4. Diopside is found commonly in which of the following transparency classifications?
   Transluscent
   Semi-transparent
   Opaque
   All of these

5. The refractometer, when used properly with a monochromatic sodium light source, may yield a birefringence value for yag of?
   0.017
   0.002
   None of these
   0.010

6. The refractometer, when used properly with a monochromatic sodium light source, may yield a refractive index value for the hexagonal, uniaxial gemstone quartz of?
   1.702
   1.544
   1.383
   1.801

7. Which of the following gemstones can be commonly found in the transluscent form?
   Diopside
   Beryl
   All of these
   Plastic

8. The Moh's hardness of corierite can be?
   6.800
   7.700
   None of these
   6.600

9. Quartz is known to exhibit which of the following streak plate responses?
   Reddish brown
   Yellowish brown
   White
   Crimson red

10. Which of the following gemstones can exhibit the phenomena of chatoyancy?
    Chrysoberyl
    There is no single best answer
    Andalusite
    Tourmaline

11. The Moh's hardness of shell can be?
    4.800
    3.900
    None of these
    3.800

12. The Moh's hardness of moldavite can be?
    6.700
    6.900
    5.500
    5.700

13. Which of the brown, opaque gemstones listed below can exhibit the conchoidal fracture characteristics and vitreous luster of the gemstone synthetic spinel verneuil?
    Stontium titanate
    Conchiolin coral
    Calcite
    Tourmaline

14. Olivine is known to exhibit which of the following streak plate responses?
    Colorless
    Reddish brown
    Lead gray
    Gray

15. Spessartite should always float in which of the following specific gravity fluids?
    3.05
    None of these
    3.32
    2.62

16. Fluorite is known to exhibit which of the following streak plate responses?
    Silver white
    White
    Greenish yellow
    Iron black

17. Which of the yellow, transluscent gemstones listed below can exhibit the granular fracture characteristics and greasy luster of the gemstone serpentine?
    Glass
    Jadeite
    Chrysoberyl
    Tortise shell

18. Hematite is known to exhibit which of the following streak plate responses?
    Cherry red
    Indigo blue
    Silver white
    Brownish black

19. Which of the following gemstones exhibits a characteristic strong band at 453 nanometers?
    Spodumene
    Synthetic rutile
    Olivine
    Diamond

20. Synthetic Corundum Verneuil is known to exhibit which of the following phenomenas?
    Girasol
    Adularescence
    Color change
    Orient

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