15 Questions
What is the primary reason for the high value of fine-quality blue sapphires?
Their unique color and saturation
Which country is a significant source of fine-quality blue sapphires?
Madagascar
What is the term used to describe the finest blue sapphires?
Kashmir
What causes the blue color of sapphire?
Presence of iron and titanium
What is the characteristic of Yogo Gulch sapphires?
Small size and saturated blue color
Why are cutters concerned about color zoning in sapphires?
It affects the color and value of the stone
What is the primary purpose of heat treatment in blue sapphires?
To enhance their color and saturation
Which country is a major source of dark blue, commercial-quality sapphires?
Australia
What is the significance of Kashmir sapphires in the market?
They are considered the finest blue sapphires
What country is the number one consumer of blue sapphire?
US
High levels of iron make basalt-related sapphires more what ?
Darker
Heat treated geuda and dhun sapphires make up a significant part of what area of the market?
Commercial
Who is the leading exported of blue sapphire to the US by volume and value ?
Thailand
Most common Synthesis method of blue sapphire ?
Flame Fusion
What is the trade term used for blue corundum ?
Sapphire
Study Notes
Blue Sapphire Overview
- Fine-quality, untreated blue sapphires make up a small but extremely valuable segment of the sapphire market.
- Blue sapphire is one of the most popular colored stones, especially in the US.
Sources of Blue Sapphires
- Madagascar has become a significant source of good- to fine-quality blue sapphire.
- Most fine sapphires over 100 carats are from Sri Lanka.
- Australia is one of the world’s major sources of dark blue, commercial-quality sapphires.
- Yogo Gulch sapphires are characterized by small size and saturated blue color.
Color and Quality
- The most highly valued blue sapphires are velvety blue to violetish blue, in medium to medium-dark tones, with strong to vivid saturation.
- The trade term “Kashmir” refers to what many consider the finest blue sapphires.
Formation and Characteristics
- The trace elements iron and titanium cause the blue of sapphire.
- Higher levels of iron make basalt-related sapphires darker than non-basaltic sapphires.
- Cutters must consider color zoning, a common sapphire characteristic.
Treatment and Market
- Most blue sapphires are heat-treated to improve their appearance.
- Heat-treated geuda and dhun make up a significant portion of the commercial-quality blue sapphire market.
- Thailand is a major center of the corundum trade, funneling a steady flow of gems from worldwide sources into the consumer market.
Test your knowledge about blue sapphire, its market value, sources, and characteristics. Learn about the most highly valued blue sapphires and their properties.
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