GIA's Gübelin Gem Project: Corundum


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Corundums (ruby and sapphires) occur in all colours of the spectrum, and have remained popular gemstones from ancient times to the present day. Photo by Robert Weldon/GIA
Ruby and sapphire (usually blue, but also in every other colour) have been the most important coloured gemstones for several thousand years. Originating historically in south-east and central Asia, and more recently in eastern Africa, these coloured varieties of the mineral corundum have been much sought as gems because of their rarity, colour and durability. Gem corundum can display asterism and chatoyancy due to the presence of oriented mineral inclusions, and in some cases, a change of colour when viewed under different light sources.
 
33066


1.77 ct Corundum - Ruby
Myanmar (PDF)

 
33068


1.62 ct Corundum - Ruby
Nepal (PDF)

 
33069


2.02 ct Corundum - Ruby
Sri Lanka (PDF)

 
33070


3.05 ct Corundum - Ruby
Sri Lanka (PDF)

 
35115


2.47 ct Corundum - Ruby
Thailand (PDF)

 
35103


1.92 ct Corundum - Sapphire
Cambodia (PDF)

 
34572


2.97 ct Corundum - Sapphire
Myanmar (PDF)

 
33081


3.46 ct Corundum - Sapphire
Myanmar (PDF)

 
33085


4.38 ct Corundum - Sapphire
Myanmar (PDF)

 
34575


5.78 ct Corundum - Sapphire
Myanmar (PDF)

 
33078


6.40 ct Corundum - Sapphire
Myanmar (PDF)

 
35147


3.89 Corundum - Sapphire
Thailand (PDF)

 
35146


3.97 ct Corundum - Sapphire
Thailand (PDF)

 
34581


6.99 ct Corundum - Sapphire
Myanmar (PDF)

 
34580


8.29 ct Corundum - Sapphire
Myanmar (PDF)

 
33092


3.48 ct Corundum - Sapphire
Sri Lanka (PDF)

 
33074


4.51 ct Corundum - Sapphire
Sri Lanka (PDF)

 
33075


6.36 ct Corundum - Sapphire
Sri Lanka (PDF)

 
33061


7.74 ct Corundum - Sapphire
Sri Lanka (PDF)

 
33063


8.70 ct Corundum - Sapphire
Sri Lanka (PDF)

 
33079


9.16 ct Corundum - Sapphire
Sri Lanka (PDF)

 
35144


4.94 ct Corundum - Sapphire
Thailand (PDF)

 
35128


5.28 ct Corundum - Sapphire
Thailand (PDF)

 
33084


15.87 ct Corundum - Sapphire
Sri Lanka (PDF)

 
33087


4.29 ct Corundum - Sapphire
Tanzania (PDF)

 
33077


5.06 ct Corundum - Sapphire
Tanzania (PDF)

 
35138


2.20 ct Corundum - Sapphire
Thailand (PDF)

 
35095


2.72 ct Corundum - Sapphire
Thailand (PDF)

 
35111


2.72 ct Corundum - Sapphire
Thailand (PDF)

 
33080


2.86 ct Corundum - Sapphire
Thailand (PDF)

 
35112


3.01 ct Corundum - Sapphire
Thailand (PDF)

 
35113


3.39 ct Corundum - Sapphire
Thailand (PDF)

 
35110


3.76 ct Corundum - Sapphire
Thailand (PDF)

 
33091


7.65 ct Corundum - Sapphire
Thailand (PDF)