Assignment 27 - Organics and Collectors’Stones Flashcards
What are the ancient origins of many organic gems?
Archeologists have found amber artifacts dating as far back as 10,000 BC.
Coral’s earliest known use in jewelry dates back 30,000 years. Besides using coral ornamentally, ancient peoples attributed magical powers to it. Among other benefits, coral was thought to protect its wearer from death.
The earliest known decorative use of ivory is a small head carved from mammoth ivory about 30,000 years ago.
Why is it necessary to protect some organic gem sources?
Over-harvesting and pollution have almost wiped out red coral along the sea’s African and European coasts
How are organic gems used in jewelry?
Artisans fashion calcareous coral into beads, cabochons, carvings, and cameos.
You’ll see ivory in jewelry as carvings, cabochons, beads, and bangle bracelets. Artisans shape ivory with saws, drills, and lathes. Like wood- workers, they use chisels to carve ivory, and finish it by burnishing and polishing the surface to a high luster.
Circular marks sometimes left in amber when treaters heat and oil it.
Sun spangles
What is a collectors’ gem?
A gem that is rare and not well known to consumers.
What has led many collectors’ gems to become more commonly used in
jewelry?
Television marketing
How is the presence of collectors’ gems increasing in the mainstream gem market?
Television marketing
Tortoise shell is composed of
A. resin.
B. protein.
C. calcium.
D. aragonite.
B. protein.
Jet is an ornamental form of
A. resin.
B. calcium.
C. conchiolin.
D. lignite coal.
D. lignite coal.
Which of the following gems is a natural glass?
A. Sphene
B. Kyanite
C. Fluorite
D. Moldavite
D. Moldavite
What’s coral’s most attractive color?
The most valuable red coral is an intense red that dealers call oxblood.
What is the most important coral marketing center?
Italy.
Because Italy is the most important coral-marketing center, many coral color terms are Italian.
The major source of jet is
A. England.
B. Australia.
C. South Africa.
D. the United States.
A. England.
The only source of gem-quality benitoite is
A. Mogok.
B. Ratnapura.
C. California.
D. the Umba River Valley.
C. California.
Which of the following is a calcium carbonate?
A. Jet
B. Amber
C. Pink coral
D. Golden coral
C. Pink coral
What are the two types of gem coral?
There are two basic types of gem coral: calcareous coral and conchiolin coral.
Calcareous coral is principally calcium carbonate in the form of calcite. Calcareous coral colors include white, cream, pink, various shades of red and orange, blue, purple, and a light grayish violet called “lavender” in the trade.
Conchiolin coral is also the skeleton-like remains of marine-animal colonies. But its principal ingredient is a protein. It includes Golden coral and black coral.
In Hawaii, black coral is
A. extinct.
B. freely harvested and sold.
C. protected as an endangered species.
D. only harvested by native Hawaiians.
C. protected as an endangered species.
Paua is a Maori name for
A. helmet shell.
B. abalone shell.
C. calcareous coral.
D. conchiolin coral.
B. abalone shell.
Which of the following organics shows a structure called “engine turning,” which looks like lines created on a lathe?
A. Shell
B. Coral
C. Ivory
D. Corozo nuts
C. Ivory
What are the primary sources of amber?
The Baltic Sea region and the Dominican Republic are amber’s principal sources.
What’s the minimum age for tree resin to be called amber?
To be called amber, tree resin has to harden over time and be at least a million years old.
Otherwise, it’s called copal, or immature amber.
Which amber color is most valuable?
A. Red
B. Brown
C. Yellow
D. Golden
A. Red
Transparent red amber is more valuable than golden amber, which is more valuable than yellow amber.
