Billions of years old and traveling at speeds up to 17,000 miles per hour, meteorites inspire the imagination. Having survived the entry through the earth's atmosphere, as well as the collision landing, they are rare finds. The ones that do survive vary greatly in size, from rocks similar to sand grains up to the 66-ton meteorite found in Namibia. Meteorites are classified into one of three types based on their iron-nickel content: "iron," "stony-iron" and "stony." Iron meteorites are over 90% metal; stony-irons have about an equal amount of iron and silicate crystals; and stony meteorites are almost entirely silicate material.
Instructions
1. Determine the type of meteorite you have. Since stony-irons account for less than 2% of meteorites, you're probably dealing with an iron or stony meteorite. Iron meteorites are more than twice as dense as stony ones, so they also attract a magnet with greater force.
2. Choose the appropriate saw blade. Unless the meteorite is quite small, you'll want to use a horizontal band saw rather than a hack saw. Standard lapidary diamond-bladed saws will work with stony meteorites, but slicing through iron requires a silicon carbide blade. The diameter of the blade should be larger than the diameter of the cut you want to make. That way, you can cut an entire slice without having to reposition the meteorite. The thickness of the blade will be determined by the type of cut. Cutting off a few slices might be possible with a thinner blade, while cutting it into equal slices would be better achieved with a thicker blade.
3. Clamp the meteorite securely in place. Start the cut slowly to prevent the saw from moving across the meteorite before creating the first channel cut. Continue to saw steadily and slowly.
4. Remove the saw marks from each slice by working up through different sandpaper grades. Begin with a belt sander with 80- to 120-grit sandpaper and carefully sand the exposed faces of the slices. Next, work a sheet of 200 grit wet-dry sandpaper across the meteorite by hand. Continue the cycle of hand sanding and increasing the grit until you reach 1200 or 1500 grit sandpaper.
5. Etch the meteorite cuttings by placing them in a solution of 5% nitric acid and 95% isopropyl alcohol; etching brings out the otherwise-hidden crystalline structure. The amount of time etching requires varies from one to five minutes, according to the size of the piece and the temperature. Check a slice every minute to see how the etch is progressing.
6. Clean the cuttings by soaking them in distilled water for five minutes and then in isopropyl alcohol for one to three days. Remove them from the alcohol and heat them in a 150% oven until they're completely dry.
7. Apply a protective coating to prevent the meteorite from rusting. Oils and grease, such as WD-40 or Rig, are typically used. Melted paraffin and lacquer are also effective.
Tags: across meteorite, five minutes, Iron meteorites, isopropyl alcohol, stony meteorites
