The Amazing Ruby - A "Tectonic" Gemstone

Posted on September 11, 2013 by Brad Bilsten | 0 Comments

Robert Stern, geoscientist at the University of Texas, is the lead author of the scientific proposal to call ruby and jadeite "plate tectonic gemstones" as they have been linked to the gemstones being created when tectonic plates collided.  Scientists want to officially link precious gems to their geological setting and this will help researchers and the general public recognize the special conditions that create rare gems.

Recognition of the PTG's links modern concepts of plate tectonics to economic gemstone deposits and ancient concepts of beauty, and may aid in exploration for new deposits.

The rare ruby featured above is the 23.1 ct Carmen Lucia gemstone that was donated to the Smithsonian Institute.  Ruby, the red gem variety of corundum, forms when melting of mixed aluminium-rich and silicon-poor protoliths.  (A protolith is an original, unmetamorphosed rock from which a given metamorphic rock is formed).  

Most ruby deposits formed during collisions with tectonic plates in East Africa, the supercontinent Gondwana (Gondwana included most of the landmasses in today's Southern Hemisphere, including Antartica, South America, Africa, Madagascar and the Australian continent, as well as the Arabian Peninsular and the Indian subcontinent which have now moved entirely into the Northern Hemisphere),  or in South Asia and the ruby gemstone is therefore a robust indicator of continental collision.

(Courtesy of and

Posted in aluminium, Australia, continent, gemstones, geologists, Gondwana, India, rare, ruby, silicon, South America, South Asia, tectonic plates

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