◂ BACK TO GEM ENCYCLOPEDIA
Sapphire
The name “sapphire” can also apply to any corundum that’s not ruby red, another corundum variety.
See Gem As
Tools
Research
Low-Temperature Heat Treatment of Pink Sapphires from Ilakaka, Madagascar
Studies the effects of low-temperature heat treatment on inclusions in this gem material, as well as the use of FTIR spectroscopy to detect the treatment.
A Quantitative Description of the Causes of Color in Corundum
Presents a quantitative means of determining the causes of color in a gem material, using corundum’s six major chromophores as an illustration.
Geographic Origin Determination of Blue Sapphire
In some cases, the value of a sapphire depends strongly on its geographic origin. This article details the origin data GIA has collected for blue sapphire and describes its methodology for using the data in geographic origin determination.
Field Gemology: Building a Research Collection and Understanding the Development of Gem Deposits
With more than 90 field expeditions on six continents since 2008, GIA has accumulated over 22,000 colored stone reference samples. This extensive collection of colored stones with known origins supports GIA’s research on geographic origin determination.
The Geographic Origin Dilemma
An overview of the geographic origin complexities facing the gem and jewelry industry today.
A Review of Analytical Methods Used in Geographic Origin Determination of Gemstones
Geographic origin determination relies on a combination of gemological observations and advanced analytical tools. This contribution reviews the analytical methods commonly used to establish origin.
Geology of Corundum and Emerald Gem Deposits: A Review
Over the last two decades, knowledge of the formation of gem deposits has improved significantly. This article reviews the state of our knowledge of the geology and genesis of gem corundum and emerald deposits.
Mineral Inclusions in Ruby and Sapphire from the Bo Welu Gem Deposit in Chanthaburi, Thailand
Identifies mineral inclusions in corundum from this locality for comparison with other global deposits.
Madagascar Sapphire: Low-Temperature Heat Treatment Experiments
Shows how the color of Madagascar sapphire is lightened with heating to relatively low temperatures below 1350°C.
The Talisman of Charlemagne: New Historical and Gemological Discoveries
Reveals new details about this historical jewel and the results of its first gemological analysis.
U-Pb Ages of Zircon Inclusions in Sapphires from Ratnapura and Balangoda (Sri Lanka) and Implications for Geographic Origin
Establishes a metamorphic origin for sapphire samples from these deposits, supported by their trace-element composition and inclusion characterization, including the age dating of zircon inclusions.
Land of Origins: A Gemological Expedition to Ethiopia
Documents a visit to the sapphire, opal, and emerald mining and trading areas of Ethiopia.
