Under close examination the small, purple spheres composing grape agate are covered in tiny, druzy crystals. Grape agate, a botryoidal form of amethyst. Elongated geodes from this area are often referred to as amethyst cathedrals. Uruguay tends to produce darker colored material that is more valuable than much of the Brazilian material that is available in larger quantities. Several companies mine these geodes from the hard basalt in the region.
The volcanic deposits in Southern Brazil and Uruguay are famous for producing spectacular purple crystal filled geodes, sometimes up to gigantic sizes. Because quartz is in such high abundance in igneous, metamorphic and sedimentary rock, it can be assumed that amethyst is quite widespread as well. The necessary minerals for amethyst formation precipitate into these cavities, depositing crystals (most often in an even layer) along the inner wall of the geode.Īmethyst is found worldwide in nearly any location where iron was present during the formation of quartz, prior to some amount of natural gamma radiation.
Amethyst formation within a geode - While there is yet to be a conclusion as to how geodes form, it's widely accepted that they form by means of solidification of gas bubbles (vesicles) within basaltic lava during igneous rock formation and in round cavities within sedimentary rock. In some instances, a surplus of these minerals will result in a solid vein of quartz or amethyst, where individual crystals can no longer be identified. The crystals will continue to grow as long as they're provided with the environment necessary for formation. Long crystals, also known as spears, can form in these cavities when the solution drips more from one location of the rock than the other, explaining why vugs often form a wide variety of crystals sizes in close proximity. Amethyst formation within a vug/cavity - Silicon and iron-rich fluids will deposit themselves along the walls of the rock cavities. These cavities most often occur by means of tectonic activity, hollow tubes formed by lava, dissolution (break down of rock resulting in cavities) or even as solidified bubbles of gas within the earth(geodes). In this environment, the silicon atoms will bond to oxygen and begin building layers that overtime result in cavities lined with thousands of crystals. This combination typically occurs when water that's high in silicon content (often gained through the break down of the surrounding rock) seeps through cracks in rocks and ends up exposed to oxygen within cavities. Quartz is primarily made up of two elemental components, silicon (Si) and Oxygen (O), both of which are in high abundance on our plant. Though to truly understand this, we have to first understand how quartz forms. Often, these iron impurities are modified by natural irradiation from the surrounding rocks or host rock, giving the amethyst (quartz) its purple color. If you are in the market for a massive amethyst geode contact us and we can work with our partners in Uruguay to source something truly impressive for you.Īnother massive specimen, an amethyst cathedral measuring a staggering 21 feet high.Īmethyst forms when iron impurities make their way into silicon-rich solutions during the formation of quartz, which can occur through hydrothermal processes or the precipitation of mineral rich waters.
Dubbed the " Enchanted Cave" it was reportedly found by a farmer in Artigas, Uruguay and is pictured below. It measures an astounding 18 feet (5.5m) wide. But that record is dated and there are potentially several that have been found eclipsing that size.Ī more recently discovered amethyst geode currently located at the Crystal Castle & Shambhala Gardens in Australia weighs in at over 44,000 lbs (20,000 kg). It measures 9 feet 10 inches (3m) long, 5 feet 10 inches (1.8m) wide and is 7 feet 2 inches (2.2 meters) high. Amethyst geodes over 1m across are routinely excavated and can fetch a substantial amount of money being sold as show stopping, display pieces.Īccording to Guinness World Records, the amethyst one is a 28,660 lb (13,090 kg) behemoth currently located at the Shandong Tianyu Museum Of Natural History in China.
The 120 million old basalt flows near Artigas, Uruguay has produced some truly monstrous geodes which formed in gas bubbles that were trapped within molten lava as it cooled. It is very popular as a gemstone in jewelry and larger crystals and geodes are in high demand as impressive display pieces. An amethyst crystal cluster from the Democratic Republic of the Congo with particularly large crystals and deep coloration.Īmethyst is considered to be a semi-precious gemstone which has been revered throughout history, but can also be found in large, crystal filled geodes.
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