Alto Uruguai Amethyst.
In 2011 I travelled to southern Brazil to visit the small Amethyst mines at Alto Uruguai to learn more about the origin of some of the world’s most glorious Amethyst.
In the southern region of Brazil, only 200 miles north of the Uruguayan border lies one of the finest discoveries of Amethyst on the planet in the state of Rio Grande. Alto Uruguai is a hilly district in Rio Grande do Sul (the southernmost state of Brazil) the area is very rural and sparsely populated, with most people living in isolated farmhouses on small farms. The mining area’s name is taken from the great river “Rio Uruguai” which travels through Southern Brazil dividing the two states of Santa Catarina and Rio Grande do Sul and then forms part of the border with Uruguay and Argentina.
The warm, temperate climate is good for arable farming, with the main crops being soya, maize and beans. What of course interests us the most is what happens under the soil in Alto Uruguia: the discovery of gorgeous Amethyst with vivid colour and great clarity. The area is not just famed for its purple Amethyst, but also Amethyst that when irradiated turns a stunning green colour (also known as Prasiolite) and breathtaking Lavender Quartz.
Alto Uruguia Amethyst was formed just before the Jurassic Period when large masses of volcanic lava were flowing from low lying volcanic activity in Southern Brazil. Often trees would get swept along with the lava and over many years these would rot inside the solidified lava and form large pockets (known in geology as vugs). Other pockets were formed in the lava by gas bubbles. Then over a period of thousands of years a hydrothermal process (the movement of hot water) mixed with a cocktail of elements such as iron stopped to rest in these large pockets and formed geodes. Whilst at first glance you would easily overlook their dull grey outer, once cracked open some geodes have a beautiful coloured interior. When did this geological wonder occur? Well, it was during the Cretaceous Period (hence the word cretaceous rock) which started in the Jurassic Period 144 million years ago and is believed to have ended approximately 65 million later.
All of the mines in the region are underground and are mined by small teams, using a combination of explosives, pneumatic drills, hammers and chisels. Many of the tunnels are around two metres high, just enough height to get small carts and basic trucks inside to extract the ore. We all know the jeep stands for “just enough essential parts”, well the truck in the picture on the previous page which miners use to get to the rock face takes the meaning to different level! Mining in the area is a very slow process, as the rock in which the geodes are found is incredibly strong. Depending on its size, once a geode has been discovered the actual extraction process can take several days.