# Shared Flashcard Set

## Details

Colored Stones-GIA
(part III)
74
Geology
09/27/2011

Term
 Most colored stones are sold
Definition
 by weight
Term
 What category of colored stone is often sold per peice?
Definition
 small, inexpensive
Term
 What category of colored stone is often sold per peice?
Definition
 Small, inexpensive
Term
 Sieves are most useful for sorting round gems with diameters
Definition
 3 mm and below
Term
 When you first start to count a large pile of small gems, it's best to separate them into groups of
Definition
 5
Term
 The color of a sorting pad should be
Definition
 neutral
Term
 Colored stones with higher values usually have
Definition
 medium to medium-dark tone and vivid saturation
Term
 If an emerald weighs 3.50 carats and the stone's cost is \$10,500.00, what is it's per-carat price?     (Divide \$10,500 by 3.50 cts.)
Definition
 \$3.000.00
Term
 If a parcel of carats weighs 382.00 cts. and the per-carat price is \$80.00, what is the total cost of the parcel?   (Multiply the parcel's carat weight by the price per carat.)
Definition
 \$30,560.00
Term
 If a parcel of amethysts contains 1,000 stones and weighs a total of 1,542.00 with a cost \$0.75 per carat,what is the unit price?   (Multiply 1,542.00 cts (parcel total weight) by \$0.75 (price per carat) for the parcel price of \$1,156.00.  Divide \$1,156.00 by 1,000 (total # of stones in the parcel) for the unit price of \$1.1565 rounded to \$1.16.
Definition
 \$1.16
Term
 What is the cost of a ruby that weighs 5.76 cts.and has a per-carat price of \$5,500.00?   (Multiply 5.76 cts. by \$5,500.00)
Definition
 \$31,680.00
Term
 Which type of rough is usually faceted?
Definition
 Highly included
Term
 To retain as much weight as possible from rare, high-quality rough, cutters would most likely vary
Definition
 proportions
Term
 Removing heavly included sections from gemstone rough by carefully tapping it with a small hammer is known as
Definition
 cobbing
Term
 Rough that's ground to the approximateshape of the finished stone is called
Definition
 preform
Term
 Which is most likely to undergo cobbing?
Definition
 Commericial-quality amethyst rough
Term
 Which cutting stage has the greatest impact on the value of the finished gem?
Definition
 Preforming
Term
 Which colored stone variety has cutting challenges due to the vunerable cleavage planes?
Definition
 Tanzanite
Term
 Translucent to opaque rough is often cut into a
Definition
 Brillant cut
Term
 Which is a carved design that projects slightly from a flat or curved serface?
Definition
 Cameo
Term
 Colored stones cut flat with shallow pavillions usually have areas of lower color intensity called
Definition
 windows
Term
 A cutter can darken the color of a pale stone by cutting a
Definition
 deep pavillion
Term
 to judge brilliance, view the stone
Definition
 Face up
Term
 The purpose of most variations in a colored stone's face up outline is to
Definition
 save weight
Term
 Excessive bulge on a step cut
Definition
Term
 Colored stones that rate "fair" for brilliance have
Definition
 between 25 and 40 percent brilliance
Term
 What is Myammar's most important gem export?
Definition
 ruby
Term
 Which location produces the majority of rubies that end up in mass-produced jewerly?
Definition
 Mong Hsu
Term
 Which trade term describes a mixture of gem qualites that represents unsorted production from a particular mine?
Definition
 Mine run
Term
 Which term describes a specific rough gemstone quality range, usually determined by color, size, clarity and price?
Definition
Term
 Where is rough from Mong Hsu brought into Thailand?
Definition
 Mae Sai
Term
 In mining terms,the theft of a mine's productiom by it;s workers is known as
Definition
Term
 Which of the following is a quantity of stones, sometimes of similar size and quality, from a single mine or from many different sources?
Definition
 Parcel
Term
 Which of these is a cutting center for colored stones in Thailand?
Definition
 Chantaburi
Term
 Materials cut free size are normally
Definition
 Large, important stones
Term
 Gemstones cut to fit standard mountings are known as
Definition
 calibrated sizes
Term
 The market sector where better-quality gemstones are used in well-finished, moderately priced jewerly is known as
Definition
 middle market
Term
 Which term describes a random sample from a parcel of gemstones, often used to asses the parcel's overall quality?
Definition
 Cut
Term
 Which of the following is a price for buying an entire parcel of gems, or a substantial part of it?
Definition
 Lot price
Term
 Which of the following is a premium price for selecting stones from a parcel?
Definition
 Pick price
Term
 Which gemstone occurs in almost every color?
Definition
 Tourmaline
Term
 The first impression of an object's basic color is it's
Definition
 hue
Term
 Generally, cool-colred hues with low saturation look
Definition
 bluish
Term
 Use trade terms that imply geographic orgin only if the
Definition
 gem's actual source is known.
Term
 Which trade term describes certain tourmalines?
Definition
 Paraíba
Term
 Which abbreviation does the GIA Colored Stone Grading System use for a slightly purplish red hue?
Definition
 slpR
Term
 In practice, what GIA Colored Stone Grading tone levels apply to grading transparent colored stones?
Definition
 2 through 8
Term
 A see-through area in a transparent gemstone's bodycolor that usually results from the way the gem was cut is called
Definition
 a window
Term
 A window usually differs from the rest of the stone in
Definition
 saturation
Term
 Extinction results from
Definition
 deep pavillions
Term
 The color of the background for grading a colored stone should be
Definition
 neutral
Term
 What type of lighting is best for grading color in a colored stone?
Definition
 Daylight-equivalent flurescent
Term
 Higher levels of saturation are usually found in stones with
Definition
 dark to very dark tone
Term
 What two coloring agents are usually responsible for color change in gemstones?
Definition
Term
 Emission of visable light by a material when exposed to invisible ultraviolet radiation is
Definition
 fluorescence
Term
 A characteristic or irregularity confined to the surface of a polished gemstone is a
Definition
 blemish
Term
 An angular, hollow space that resembles a mineral inclusion is called a
Definition
 negative crystal
Term
 A general term for a break in a stone is
Definition
 feather
Term
 An inclusion with the most negative effect on a colored stone's clarity would be located
Definition
 under the table
Term
 In which colored stone clarity type are the gems usually eye-clean?
Definition
 Type I
Term
 The highest clarity grade for a colored stone is
Definition
 eye-clean
Term
 The term "silk" describes
Definition
 a group of fine, needle-like inclusions
Term
 Fingerprints are
Definition
 Partially healed fracture planes
Term
 Fingerprints are
Definition
 Partially healed fracture planes
Term
 Which of these gems are classified as a Type III?
Definition
 Emerald
Term
 In which of the following colored stone clarity grades do the definitions vary for each clarity type?
Definition
 Moderately included
Term
 Which of these clarity characteristics would usually have the greatest impact on a gem's marketabiltiy?
Definition
 A large, unhealed feather
Term
 Gems that are usually eye-clean include:
Definition
 spodumene, yellow beryl and aquamarine
Term
 Inclusions are important to gemologists because they
Definition
 Can help separate natural from synthetic gems
Term
 Growth zoning in a colored stone is evidence of
Definition
 crystal growth
Term
 Two factors that determine an inclusion's impact on a gem's value are
Definition
 position and relief
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