Colored Stones GEM 220 Quiz Study Guides

(Q2) If a 5-ct. amethyst costs $50, its per-carat price is?

- $10

(Q2) There are 12 stones in a parcel, and the parcel costs $5400. What is the unit price?

- $450

(Q2) The international unit of measurement for expressing gemstone weight is the carat, which is?

- 0.20 gram

(Q2) How many 2-point stones are in a parcel with a total weight of one carat?

- 2 To review this topic and find the correct answer, see "Carat Weight and the Gem Business" in Colored Stones Assignment 11.

(Q1) The term "seed crystal" is defined as:

- A tiny crystal used as the template for gem growth.

(Q1) The term used to describe a gem that is colored by trace elements in its crystal structure is?

- Allochromatic

(Q1) The type of deposit that's most likely to be found miles away from the original source rock is?

- Alluvial

(Q1) All doubly refractive gems have at least one singly refractive direction?

- Along the optic axis

(Q1) A characteristic enclosed within a gemstone is called:

- An inclusion

(Q1) The relationship of aquamarine to beryl is?

- Aquamarine is a variety of beryl.

(Q2) Lattice diffusion with titanium can create?

- Asterism

(Q1) Major sales outlets that often see record-breaking prices from the sales of fine gems and jewelry are?

- Auction houses

(Q1) The three basic types of surface modification are coating, painting, and?

- Backing

(Q1) A rock must...

- Be composed of masses of many crystals.

(Q2) After irradiation treatment, the colors of yellow and orange sapphires will...

- Be unstable

(Q1) The concept of reserving a portion of the resources derived from a country for the economic development of that country is called?

- Beneficiation

(Q1) When cobalt is present in either synthetic spinel or some fine natural spinel, this produces?

- Blue

(Q1) The elongated synthetic crystal produced by flame fusion or pulling methods is called a?

- Boule

(Q2) The colored stone cut that most effectively conceals inclusions is the?

- Brilliant cut

(Q2) A ruby with a low number on the GIA saturation scale would appear?

- Brownish

(Q1) To produce large quantities of identical jewelry pieces for the commercial market, a manufacturer would need to find a good supplier of?

- Calibrated stones

(Q1) Heat can lighten amethyst's purple by?

- Causing changes in color centers.

(Q1) The kinds and relative quantities of atoms that make up a material are defined as its?

- Chemical composition

(Q2) In its purest form, corundum is?

- Colorless

(Q2) Most defects in colored stone proportions are?

- Compromises made by the cutter to produce economically viable gems.

(Q1) Most colored stones form in the earth's...

- Crust

(Q1) A synthetic gem and its natural counterpart have essentially the same?

- Crystal structure

(Q1) The crystal system with the highest degree of symmetry is?

- Cubic

(Q1) You can be almost sure that a gem is synthetic if its growth marks are?

- Curved

(Q1) A regular, repeating internal arrangement of atoms in a material is its?

- Cystal Structure

(Q2) What characterizes Australian sapphires?

- Dark, inky blue

(Q2) For consistency, you should judge hue, tone, and saturation under what type of lighting?

- Daylight-equivalent fluorescent

(Q2) When evaluating a stone's cut, one of the first things a dealer should do is?

- Evaluate its face-up impression.

(Q1) GIA's position is that a treatment should be disclosed as part of every transaction...

- Even if it's only suspected.

(Q2) Which clarity characteristic causes the velvety appearance unique to Kashmir sapphires?

- Extremely fine rutile needles

(Q2) To judge brilliance, view the stone?

- Face-up

(Q2) When looking for clarity characteristics, light reflected from the surface can help to detect?

- Feathers and fractures.

(Q1) An example of an amorphous material is?

- Fire opal

(Q1) Low cost and high volume characterize which process?

- Flame fusion

(Q1) The emission of visible light in response to stimulation from a higher-energy light, usually X-ray or UV light, is called?

- Fluorescence

(Q2) Chromium in ruby can cause?

- Fluorescence

(Q1) To facilitate the healing of fissures during ruby heat treatment, treaters use the presence of?

- Flux

(Q1) When heat treatment takes place in the presence of gases other than oxygen—called a reducing environment—the gem tends to?

- Gain electrons

(Q1) Common fracture-filling substances include oils, resins, polymers, and?

- Glass

(Q2) Why is green sapphire used as the crown in a sapphire doublet?

- Green sapphire produces beautiful fire. To review this topic and find the correct answer, see "Imitations" in Colored Stones Assignment 14.

(Q1) The characteristic shape of a gem crystal is called its?

- Habit

(Q2) Due to lower iron levels, Sri Lankan sapphires?

- Have a bright appearance.

(Q2) The first impression of a gem's basic color is called its?

- Hue

(Q2) Generally, gem weight is stated to the nearest?

- Hundredth of a carat.

(Q2) All other factors being equal, how would the per-carat price of parcels of 2-ct. sapphires compare to the per-carat price of parcels of 0.50-ct. sapphires?

- It would be four times higher. To review this topic and find the correct answer, see "Carat Weight and the Gem Business" in Colored Stones Assignment 11.

(Q1) Visual observation of inclusions can help gemologists identify a gem as well as indicate?

- Its natural or synthetic origin

(Q2) The spinning disk coated with a polishing abrasive and used to shape facets is called a:

- Lap

(Q2) What does the word padparadscha mean?

- Lotus flower

(Q1) An organic gem is?

- Made by a living organism.

(Q2) What makes Sri Lanka such a gem-rich island?

- Many species of stones are found on the beaches. To review this topic and find the correct answer, see "Sri Lanka" in Colored Stones Assignment 13.

(Q2) The finest rubies typically form in?

- Marble deposits

(Q1) The district in Brazil that is most famous for its pegmatite deposits of tourmaline, topaz, and beryl is?

- Muzo. To review this topic and find the correct answer, see "South America" in Colored Stones Assignment 7.

(Q2) An angular, hollow space within a gem is known as a?

- Negative crystal

(Q2) Before looking at the color of a gem, clean the stone, and then pick it up by its girdle with tweezers or place it on a background that is...

- Neutral colored.

(Q2) What keeps Montana from becoming a highly productive sapphire source?

- Not enough potential yield. To review this topic and find the correct answer, see "Montana" in Colored Stones Assignment 13.

(Q1) Which of the following gems forms as the result of a sedimentary process?

- Opal

(Q1) Which is a key locality for hydrothermal gems?

- Ouro Preto, Brazil

(Q2) Extinction can be an effective way to make:

- Pale rough appear darker and more saturated.

(Q1) A quantity of stones of similar or mixed qualities, from a single mine or from various sources, offered for sale together is called a?

- Parcel

(Q2) Fingerprints are?

- Partially healed fracture planes.

(Q2) What unique feature of black star sapphires causes cutters to fashion shallow cabochons?

- Parting

(Q1) The biggest and most well-formed crystals are found in?

- Pegmatites

(Q1) Metamorphic rocks are altered by heat and?

- Pressure

(Q1) Which is a workable alluvial deposit of gem minerals with economic potential?

- Primary. To review this topic and find the correct answer, see "Eluvial and Alluvial Deposits" in Colored Stones Assignment 2.

(Q1) A treatment that causes the formation of small cracks that accept dye in a gem is called?

- Quench-crackling

(Q2) Fine-quality rubies over one carat are?

- Rare

(Q2) A star sapphire's rays should be distinct, well centered, and?

- Reach from girdle to girdle.

(Q2) Though some dealers do not distinguish between consignment and memo, those that do would expect memo goods to be?

- Returned more quickly.

(Q2) How does a GIA report describe a stone that contains more glass than ruby?

- Ruby-and-glass composite or manufactured product

(Q1) The method used to produce synthetic cubic zirconia (CZ) is?

- Skull melt

(Q1) Colored stones are most commonly mined by?

- Small groups of independent miners.

(Q1) The two main types of processes for synthetic gem production are melt and?

- Solution

(Q1) Treatment that involves wrapping opals in a carbon-rich material such as paper or dried manure and then heating is called?

- Sugar treatment. To review this topic and find the correct answer, see "Sugar and Smoke Treatments" in Colored Stones Assignment 6.

(Q2) In 1947, Union Carbide's Linde Division synthesized?

- Synthetic star ruby and star sapphire.

(Q2) Which of the following is a source for rubies that contain no silk?

- Thailand

(Q2) Proportion variations are considered acceptable in rare, expensive rough because?

- They can help the cutter retain as much weight as possible.

(Q2) A needle inclusion can be a long, thin solid crystal or a?

- Thin hollow tube

(Q2) The gem species with the largest color range is?

- Tourmaline

(Q1) Although its own gem resources have been declining since the 1960s, Thailand remains a major player in the gem industry due to its expertise in?

- Treating and cutting

(Q1) When crystal growth is interrupted and then resumes again in a different direction, this is called?

- Twinning

(Q2) In which colored stone clarity type are the gems usually eye-clean?

- Type I

(Q2) The trace element that causes the color change in sapphire is?

- Vanadium

(Q1) To best display asterism, the cutter fashions a cabochon with its reflective inclusions...

- at a 60-degree angle to the base. To review this topic and find the correct answer, see "Asterism" in Colored Stones Assignment 4.

(Q2) An off-center pavilion is considered a variation in?

- clarity. To review this topic and find the correct answer, see "Looking at the Stone from Above" in Colored Stones Assignment 9.

(Q1) One of the most doubly refractive minerals, which displays eye-visible doubling in transparent material, is?

- garnet. To review this topic and find the correct answer, see "Refraction" in Colored Stones

(Q1) The gem industry sector that Jaipur, India, is renowned for is?

- jewelry manufacturing. To review this topic and find the correct answer, see "India" in Colored Stones Assignment 7.

(Q2) Geuda sapphires are treated by heating in?

- lattice diffusion with titanium. To review this topic and find the correct answer, see "Sapphire Treatments" in Colored Stones Assignment 13.

(Q1) Lead glass makes a good fracture-filling material for ruby due to its similar refractive index, but it is?

- much harder than corundum, resulting in an uneven wear pattern. To review this topic and find the correct answer, see "Glass Filling of Corundum" in Colored Stones Assignment 6.

(Q2) The earth's most abundant elements are?

- oxygen, aluminum, and silicon.

(Q1) In gems, phenomena caused by structure are the result of?

- pleochroism. To review this topic and find the correct answer, see "Phenomena Caused by Structure" in Colored Stones Assignment 4.

(Q2) For maximum brilliance, stones with low refractive index (RI) require?

- shallow pavilions. To review this topic and find the correct answer, see "Judging Brilliance" in Colored Stones Assignment 9.

(Q2) A sign of poor finish is?

- sharp facet points. To review this topic and find the correct answer, see "Judging Gemstone Cut: Judging Finishing Touches" in Colored Stones Assignment 9.

(Q1) Which of the following best describes the fracture of an aggregate mineral like jadeite?

- smooth. To review this topic and find the correct answer, see "Cleavage, Parting, and Fracture" in Colored Stones Assignment 3.

(Q2) You should expect the most size variations in parcels of calibrated?

- tourmaline. To review this topic and find the correct answer, see "Ovals" in Colored Stones Assignment 11.

(Q2) One possible reason for cutting a small table on a brilliant cut is to improve?

- windowing. To review this topic and find the correct answer, see "Table Size" in Colored Stones Assignment 9.