On February 15, 2013, the largest known meteorite to enter our atmosphere in 100 years exploded over Russia (according to NASA). The explosion unleashed the force of 20 atomic bombs and sent a destructive shock wave that injured over 1,000 people.
Meteorites are now on the tongue of everyday people and more eyes are scanning the night sky than ever before. Inquisitive people want to know: what is a meteorite? Is this a new phenomenon? How can a meteorite produce a gemstone?
A small solar system body that orbits the sun is called an asteroid. If these bodies are less than 10 meters across, then they are referred to as meteoroids. When either of these gets drawn into Earth’s gravitational pull and enters our atmosphere, the fireworks begin. The friction and pressure of our atmosphere disintegrates most objects. If this occurs at night, we see this process as a shooting star. However, if a fragment remains and falls on Earth, it is called a meteorite. This process has been going on since the beginning of time. In fact, tons of junk hits our atmosphere every day. Thankfully, most is obliterated in the atmosphere.
Meteorites are classified into three types: stony, iron and stony-iron. Stony meteorites are by far the most common. As the name suggests, they are rocks of mostly silicate minerals. Iron meteorites are mainly iron/nickel and account for five percent of the meteorites that fall on earth. Some wellknown iron meteorites include the Campo del Cielo (field of the heavens) meteorites found northwest of Buenos Aires, Argentina. In 1576, it was documented that the Argentinian Indians were using a unique type of iron of unusual purity for their weapons. An expedition found a huge hunk of metal sticking out of the ground; they thought it was an iron mine. Over time, more and more hunks of metal were found. With carbon dating now available, the charred wood from under one of the pieces of metal was scientifically analyzed leading to a determination that the meteorites had fallen 4- to 5,000 years ago! Accounting for only one percent of the meteorites that fall on earth, stony-iron meteorites are a combination of the two. A breathtaking example of this type is the combination of iron and olivine. Olivine is a yellow/ green mineral that, in its purest form, is called peridot. When this meteorite is thinly sliced, it reveals a stained glass effect of shiny iron webbing around the transparent panes of olivine.
Sometimes when meteorites hit the Earth, something else is formed besides just an impact crater. When the force of the meteoroid vaporizes the terrestrial dirt and rock, tektites are formed. Tektites are pitted, rounded pieces of non-volcanic glass dated to be 750,000 to 35 million years old. The liquefied rock is blasted high into the air and flung away from the impact site. The most common tektite is black glass like obsidian. A rare tektite is a bottle-green color and is called moldavite. Moldavite is the only gemstone on Earth produced by a celestial body. Moldavite comes from the Czech Republic and is believed to have been formed when a giant meteorite impacted Germany 15 million years ago.
Articles are reporting that the people in Russia have already been prospecting for meteorites. Fortunately, you do not have to travel across the globe to be able to see and hold something from space. Earth’s Treasures, located at 25 N. Willson, in downtown Bozeman, has an exciting and extensive collection of meteorites, tektites and moldavite. Call 406-586-3451 or visit www.EarthsTreasuresMT.com for more information.
—By Patti Albrecht, Owner of Earth’s Treasures