Northern Uruguay is home to one of the largest amethyst deposits in the world – but their organization has long been a mystery . Using clipping - edge technique , researchers are unraveling their origin write up and have key out that these stunninggemscrystalized at surprisingly low temperature .
Amethysts are a character of lechatelierite , placeable by their striking reddish blue hue . The gemstones are an important economic resource in Uruguay , home to the Los Catalanes excavation district – a deposit so important it has been recognize as one of the “ First 1000 IUGS Geological Heritage Sites ” by the International Commission of Geoheritage ( IUGS ) . accord to theIUGS , the deposit is “ alone ” because of its high number of mega - geodes and vast reserves as well as the gemstone quality and variety .
Amethyst geodes ( some over 16 feet high ! ) are located in cool lava flow . These ancient lava stream can be traced to the breakup of the supercontinentGondwanasome 134 million years ago . Mining began in northern Uruguay over 150 years ago and keep on to be an important industriousness today . However , because not much is known about their origin , it can be tough to find new geode and much presently count on miners ’ experience .
To find out more , researchers carry out a serial of geological surveys analyzing geode minerals , groundwater and geode - host water in over 30 mine . The study involved high - tech techniques including nucleation - wait on microthermometry ( to canvas small fluid - replete scoop in the rock music ) and triple - oxygen - isotope geochemistry ( to psychoanalyse oxygen corpuscle in minerals ) .
“ The preciseness and accuracy of these young techniques allow us to estimate with self-confidence the temperature and piece of music of the mineralizing fluids , ” Fiorella Arduin Rode , lead author and PhD research worker at Göttingen University ’s Geoscience Centre , enounce in astatement .
“ Our findings support the idea that these amethysts crystallised at low temperatures from groundwater - alike fluids . ”
The results show that the amethyst geodes were formed at temperatures between 15 and 60 ° C ( 59 ° F and 140 ° F ) – a surprisingly broken temperature , the researchers say . This suggest the amethyst formed once the lava had cooled .
What ’s more , the results divulge the mineralizing fluid had low salinity concentrations . The isotope content also suggests the water came from the natural weather cycle . The researchers believe it in all likelihood originated from groundwater contained in rock close by .
Knowing this could help find more of these telling crystals in the future .
" interpret the conditions for amethyst formation — such as the temperature and makeup of the mineralising fluid , as well as the silica germ , the timing of the mineralisation , and its family relationship with the host rocks — is crucial for unravelling the process,”saidRode .
“ This could significantly improve geographic expedition techniques and result to sustainable mining strategy in the future . ”
The sketch is publish in the journalMineralium Deposita .
