UK researchers from the University of Glasgow (UOG) discovered traces of fire opal in a 1.7-gram fragment of Martian meteorite supplied by the Natural History Museum in London. The meteorite, Nakhla, was said to have landed in Egypt in 1911, millions of years after being blasted from the surface of Mars.
Although earlier NASA expeditions to Mars had indicated opal deposits existed on the red planet, UOG School of Geographical and Earth Sciences professor Martin Lee noted, “This is the first time that a piece of Mars here on Earth has been shown to contain opal.”
Although earlier NASA expeditions to Mars had indicated opal deposits existed on the red planet, UOG School of Geographical and Earth Sciences professor Martin Lee noted, “This is the first time that a piece of Mars here on Earth has been shown to contain opal.”
Despite its tiny size, Lee insisted the Martian fire opal was significant.
“Firstly, it definitively confirms findings from NASA’s imaging and exploration of the Martian surface which appeared to show deposits of opal,” he said.
“Secondly, we know that on Earth, opals like these are often formed in and around hot springs. Microbial life thrives in these conditions, and opal can trap and preserve these microbes for millions of years. If Martian microbes existed, it’s possible they too may be preserved in opal deposits on the surface of Mars.
“Closer study of Martian opals by future missions to Mars could well help us learn more about the planet’s past and whether it once held life.”
Implications for Australia
University of Sydney associate professor Patrice Rey told Jeweller that the extraterrestrial gemstone appeared to have formed under similar conditions to central Australian opal, an area of focus for his research.
In addition to confirming the close association between opal and the mineral ferrihydrite – which can also be observed in central Australia’s Great Artesian Basin – Rey stated that the discovery confirmed the role of ‘oxidative acidic weathering’ in extracting chemical material from volcanic rock to form the gemstone.
He said the same mode of weathering had also been proposed to explain how opal was formed in central Australia.
“What is exciting about this new discovery is that it emphasises that the Great Artesian Basin could be one of the best terrestrial analogues of the Martian surface,” he concluded.
The findings of Lee and his team of researchers have been published in the international journal Meteoritics and Planetary Science.
Fire opal is a volcanic-type opal that displays orange, yellow and red colouration. While the gemstone is mined locally in Western Australia, Mexico is said to be the largest source of fire opal. Smaller amounts of the gemstone can be found in other regions, including the US, Guatemala, Canada and Brazil.