What do you believe is the single most important factor driving up the cost of living in Nigeria?

Amethyst is a violet variety of quartz that has been used as a gemstone for many centuries and is a key economic resource in northern Uruguay. Geodes are hollow rock formations often with quartz crystals, such as amethyst, inside.

Amethyst geodes in Uruguay have been found in cooled lava flows, which date from the original breakup of the supercontinent Gondwana around 134 million years ago. However, their formation has remained a mystery. A research team led by the University of Göttingen has now investigated, using cutting-edge techniques. The researchers discovered that the amethyst geodes formed at unexpectedly low crystallization temperatures of just 15 to 60 °C.

Taken with their other results, researchers were able to propose a new model to explain their formation. The research is published in the journal Mineralium Deposita.

Amethyst has been mined for over 150 years in the Los Catalanes District of Uruguay, where the research was carried out. This is an area renowned for the deep violet color and high quality of its gems, as well as magnificent giant geodes sometimes over 5 m high. The deposits here have been recognized as one of the top 100 geological heritage sites in the world, highlighting their scientific and natural value.

Göttingen University researcher Fiorella Arduin Rode working in open pit mine of the study area, Los Catalanes mining district, northern Uruguay. Along with Ametista do Sul in southern Brazil, these regions are the world's leading mining districts for gems which come from volcanic lava, such as amethyst and agate geodes. Credit: Santiago Guerrero Cherma

• Read More