It is no surprise that Meteorites and their associated Impactites, have fascinated people for many centuries. They were the subjects of worship, used as ceremonial objects, or used in the creation of jewelry for royalty. In fact, a pendant belonging to King Tutankhamun has a lime-green Moldavite in the centre (Photo below by Jon Bodsworth). Their origins in space, Meteorites connected people to the stars and homes of the gods they worshipped. Meteorites and Impactites are still fascinating today as their uniqueness and scientific significance is well recognized.
Meteorites are formed when space debris is pulled into the Earth’s orbit and crashes into the surface. Impactites (which includes moldavites) are created through the intense heat and pressure of an extremely large meteorite’s impacts, which creates new materials.
All meteorites that can be found on earth come from within our solar system. Jupiter, as the largest planet in our solar system, has a very strong gravitational pull. Asteroids are sometimes pulled out of the asteroid belt between the orbits of Mars and Jupiter (see image below) by the force of Jupiter's gravity, causing them to collide with other asteroids, and creating fragments that are driven off course. Eventually - often millions of years later – the pieces can get caught in earth’s gravitational pull, and crash into the surface of our planet. Meteorites can also be bits of other planets, our moon, or comets that have likely been broken off through the impact from an asteroid.
Millions of individual bits of space debris (usually very small) hit Earth’s atmosphere or make it to the surface every day. The Moon has millions of craters, revealing how often such bodies enter our planetary neighborhood. However, our moon doesn’t have enough atmosphere to break apart meteors, resulting in larger and a greater number of meteorites hitting the surface.
Extremely large meteorites have hit the earth over our planet’s history. The largest ever found, named Hoba (Photo below by Sergio Conti), is 60 tones, and due to its immense weight, has never been moved. But, to put that in perspective, the asteroid that caused the extinction of the dinosaurs is estimated to have been between 7.52 to 14.10 trillion tons!
Although Meteorites are rocks, most are far older than any rock found on earth. In fact, some meteorites contain tiny particles that formed around other stars that existed before our Sun! Furthermore, Meteorites provide some of the only samples we have of other planets, asteroids and possibly comets in our solar system so are of great interest to astronomers.
There are three types of meteorites: stony, iron, and stony-iron. Stony meteorites are made up of minerals that contain silicates (chemicals that contain the elements silicon and oxygen) and some metal, namely nickel and iron. Iron meteorites are mostly made of iron and nickel. They come from the cores of asteroids. The most massive ever discovered, including Namibia’s Hoba meteorite are iron meteorites. Their heavy mineral composition often allows them to survive the friction through Earth’s atmosphere without breaking into smaller pieces. Stony-iron meteorites have nearly equal amounts of silicate minerals and metals. One group of stony-iron meteorites, the pallasites, contains yellow-green olivine crystals encased in shiny metal. Astronomers think many pallasites are relics of an asteroid’s core-mantle boundary.
Most meteorites look very much like rocks found on Earth, except they usually have a dark, burned exterior. As a meteor crashes toward Earth, friction from our atmosphere melts the meteorite in a process called thermal ablations that can give meteorites a roughened, smooth, or thumbprint surface (Photo right).
One of the best places to find meteorites, but not so easy to get to, is in the Antarctic. Here, they stand out against the white-blue ice (Photo below by Katie Joy). Meteorites can also be found fairly easily at the other climatic extreme, in desert areas.
If a meteorite strike is large enough (at least building-size), the great heat and pressure of the impact melts and deforms the surrounding rock, sand and soil, creating new materials called Impactite. Interestingly, because these materials have been created by heat and pressure, impactites are a type of metamorphic rock.
One type of impactite, Moldavite, has a rich emerald or olive-green color. Most moldavites are modest in size, rarely exceeding about 20 g. These gems are found in a relatively small area of the Czech Republic and may have been formed during the 15-million-year-old impact at Nördlinger Ries in Germany (Photo below by Aerolite Meteorites). They are collected to make lovely green cut stone for jewelry or just kept the way they are as irregular but beautiful green pieces.
Great Canadian Prospecting has several Meteorites and Moldavites available. Take a look at our incredibly unique and entirely one-of-a-kind pieces. When you purchase a meteorite, you are collecting a piece of an asteroid, comet or our moon that may be older than the earth itself. When you collect a moldavite specimen, you acquire a remnant from a unique event in earth’s geological history, and one that is becoming increasingly rare.
References:
American Museum of Natural History. What is a Meteorite? https://www.amnh.org/exhibitions/permanent/meteorites/meteorites/what-is-a-meteorite
New Scientist (2017). Earth’s greatest hits: Six of the biggest meteorites in history.
National Geographic (2021) Meteorite. https://www.nationalgeographic.org/encyclopedia/meteorite/
Geology.com (2021) Impactites - Ghostly Footprints Of Ancient Meteorites. https://geology.com/meteorites/impactites.shtml
Katie Joy, University of Manchester, via BBC (2020) Antarctic meteorites yield global bombardment rate https://www.bbc.com/news/science-environment-52465237
Sergio Conti (2014) Hoba meteorite. Grootfontein, Namibia. CC BY-SA 2.0, via Wikimedia Commons https://creativecommons.org/licenses/by-sa/2.0