58 Questions
What is the meaning of 'Padparadscha'?
Means 'lotus flower' in local language
Which of the following countries is NOT considered a traditional source of Padparadscha sapphires?
Myanmar
What is the trade name for purple sapphires?
All the Above
What is the term for sapphires that change color under different lighting conditions?
Color change
Which of the following countries is NOT a known source of Pink Sapphires?
Brazil
What is the term for sapphires with a star-shaped inclusion?
Star sapphire
What is the term for black star sapphire with golden or yellow rays?
Golden star
Which of the following methods is used to create red and orange corundum and star rubies?
Pulling process
What is the most common imitation material for fancy sapphires?
Glass
In which year were the first flame-fusion star rubies and star sapphires synthesized?
1947
What is the industrial use of synthetic sapphire in display screens for smartphones?
Scratch-resistant coating
Which of the following is NOT a method of corundum synthesis?
Electrolysis
What is the preferred colorless diamond substitute?
White/Colorless sapphire
Where are sapphires found in a pastel color range?
All of the above
What is the name of the method used by Russian producers to make a wide range of fancy sapphires?
Hydrothermal process and Pulling Process
What is the name of the method used to create pink and orange fancy sapphires?
Flux method
Which of the following is an industrial use of synthetic sapphire?
All of the above
Which trace elements are found in Padparadscha sapphires?
Iron and chromium
What basic hues are found in daylight-equivalent light for Color Change Sapphires?
Blue to violet
Which sapphire variant undergoes a color change from green in daylight to reddish brown in incandescent light?
Color Change Sapphire
Which sapphire is described as having a vivid blue to violetish blue color?
Blue Star Sapphire
What element causes color change in Color Change Sapphires?
Vanadium
Which type of sapphire's asterism phenomenon is caused by Hematite inclusions?
Black Star Sapphire
What is the crystal structure of sapphire?
Hexagonal pyramid or bipyramid
Which color range and tone combination best describes the finest padparadscha sapphires?
Yellowish orange to orangy red with intensely saturated tones
Which country highly values yellow sapphires due to association with royalty?
Thailand
In terms of market size, what is the status of black sapphires despite the popularity of black diamonds?
Comparatively small
What saturation level is associated with the finest yellow sapphires?
Vivid
Padparadscha sapphires are a combination of which two hues?
Pink and orange
Which sapphire variety is described as having a whole range of tones with intensely saturated combinations?
Padparadscha
From which country are natural yellow sapphires often in demand apart from Southeast Asia?
Sri Lanka
What is the characteristic of the finest orange sapphires?
strongly red-orange with medium tone and vivid saturation
Which type of sapphire has a range of tones from reddish purple to violetish purple?
Purple Sapphire
What is the characteristic of the finest yellow sapphires?
yellow to orangy yellow, with medium tone and vivid saturation
What is the characteristic of green sapphires?
blue-green to yellow-green, with light to very dark tone and usually low saturation
What is the MOHS SCALE of sapphire?
9
What is the species of sapphire?
Corundum
What is the characteristic of the most expensive star corundum?
Semitransparent with just enough silk
What is the cause of the asterism phenomenon in black star sapphires?
Hematite inclusions
What is the typical shape of the crystal structure of sapphires?
Barrel- or spindle-shaped hexagonal pyramid or bipyramid
What is the characteristic of Trapiche sapphires?
Strong bands of color that form along the crystal’s hexagonal growth zones
What is the characteristic of the body color of blue star sapphires?
Vivid blue to violetish blue
What is the characteristic of Color Change Sapphires in incandescent light?
Violetish purple to strongly reddish purple
What is the primary method used to create synthetic sapphires in a variety of colors?
Flame fusion/Verneuil method
In which area of Montana are sapphires found in a pastel color range?
Missouri River and Dry Cottonwood
What is the primary industrial use of synthetic sapphires?
All the above
Which country uses the pulling process to create red, blue, and colorless corundum?
Russia
What is the name of the method used to create pink and orange fancy sapphires?
Flux method
Which of the following is a common treatment for sapphires?
All the above
What type of sapphire is characterized by its availability in a range of colors, except red, which is classified as a star ruby?
Star Sapphire
Which type of sapphire is known for its 'alexandrite-like' color-changing properties, but is much less expensive than actual alexandrite?
Color Change Sapphire
What is the characteristic of a 'golden star' sapphire?
It has a star-shaped inclusion with golden or yellow rays
Which type of sapphire is characterized by its vibrant pink color and is highly prized in the market?
Pink Sapphire
Which country is known for producing a variety of corundum colors, including star rubies and star sapphires?
Mogok
What type of sapphire is often found in pastel colors?
Padparadscha Sapphire
Which type of sapphire is characterized by its vibrant purple color and is often referred to as 'amethystine' or 'plum' sapphire?
Purple Sapphire
Which type of sapphire is characterized by its vibrant yellow or orange color and is often found in East Africa and Southeast Asia?
Yellow Sapphire
What is the common characteristic of 'fingerprint' inclusions in fancy sapphires?
They are a type of silk inclusion
Study Notes
Fancy Sapphires
- Montana's Missouri River and Dry Cottonwood and Rock Creek areas produce sapphires in a pastel color range.
Common Treatments and Synthetic Processes
- Common treatments: heat treatment, Beryllium lattice diffusion, artificial irradiation, and glass filling.
- Main synthetic process: flame fusion/Verneuil method.
- Other synthetic processes: pulling, flux, floating zone, and hydrothermal.
- Russia uses pulling to create red, blue, and colorless corundum.
- Russian producers use hydrothermal process to create a wide range of fancy sapphires, including color-change stones.
Industrial Uses for Synthetic Sapphire
- Used in lasers, highly energy-efficient circuitry, and LEDs.
- Used in scratch-resistant display screens, fingerprint scanners, and touchscreens for smartphones.
Common Imitation Materials
- Glass is the most common fancy sapphire imitation material.
- Doublets also mimic fancy sapphire and star corundum.
- Cubic zirconia (CZ) is another imitation material.
- White/Colorless sapphire is preferred over other diamond substitutes like synthetic cubic zirconia.
Countries of Origin
- Padparadscha: Sri Lanka, Africa, and Vietnam.
- Pink Sapphire: Sri Lanka, Myanmar, Madagascar, Mozambique, Vietnam, Montana, and other locations.
- Yellow and Orange: Sri Lanka, East Africa, Australia, Montana, and Southeast Asia.
- Green: Vietnam, Thailand, Montana, and Australia.
- Purple: Vietnam.
- Black Stars: Thailand and Australia.
- Color Changing: Australia.
- Blue Star: Thailand.
Chemical Composition
- Padparadscha: traces of iron and chromium.
- Pink Sapphire: trace elements chromium.
- Purple Sapphire: varying combinations of iron, titanium, and chromium.
- Yellow & Orange: trace elements iron and possibly chromium, or from color centers, basaltic material.
- Green: a mixture of two different color-causing mechanisms: yellow, caused by iron, and blue, caused by an iron and titanium intervalence charge transfer.
- Color Change: trace element is vanadium.
Crystal Structure and Possible Phenomena
- Barrel- or spindle-shaped hexagonal pyramid or bipyramid.
- Possible phenomena: asterism, color-change.
Clarity Characteristics
- Star Sapphire: tiny, needle-like inclusions rutile, usually made up of 2, 3, or 6 intersecting bands, resulting in 4, 6, or 12 rays.
- Trapiche sapphire: extremely rare, with strong bands of color that form along the crystal's hexagonal growth zones.
This quiz covers the characteristics of sapphires, including inclusions, cuts, and trade names. Test your knowledge of these precious gemstones!
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