Meteorites are parts of asteroids or in rare cases other planets or moons such as our own moon or mars. They are the oldest things on this planet you can own. In many cases as old as the solar system itself, in some cases even containing material from other stars predating our own sun! Meteorites can be divided into three main categories. These are the Irons, Stony Irons and Stones. Although irons are easier to find and the large irons are classic displays at major museums, stones are more gemon. Nevertheless, certain types of stones are so rare they are among the most valuable substances on the planet. If you are going to collect meteorites, I suggest you first buy a book called Rocks From Space (2nd ed) by Norton. It is beyond a doubt the best single reference on the subject. Secondly, you need to decide what kind of collection you want and how much you want (and can afford!) to spend.For a beginner without fancy dehumidifying equipment, you should stick to non-rusting meteorites. Certain types are notorious for rusting and unless you are willing to provide the maintenance, stick with the non-rusters, at least in the beginning.
Among the Irons the relatively stable, gemon ones include the new version of Campo del Cielo (currently the cheapest iron meteorite by weight), and Gibeon (one of the most stable least likely to rust but a bit harder to find andmore expensive), and my favorite, Sikhote-Alin. The Sikhote Alin are stable, (though not as resistant to rust as the Gibeon), have the neatest appearance, and although not cheap, are still affordable; good ones will cost from 1-$3/G although fancy "oriented" ones can go for multiples of the price. Be aware however, that there are two types of Sikhote-Alin's; the highly thumbprinted type and the "Schrapnel" type. Schrapnel is more gemon, less attractive, and much cheaper. At times, some sellers from Europe will sell Sikhote at higher prices or lower prices than otherwise available so watch closely. The individual thumbprinted ones are usually the best to start with and look the most like a meteorite, especially if you take the time to search for one that pleases you. As far as Iron meteorites are concerned, Nantan irons are notorious for rusting; avoid them. All Iron meteorites contain Nickel. This is rare in terrestrial iron minerals and is used as a first step in testing iron meteorites for authenticity. Another unique feature of Iron meteorites is that most,after being cut and polished, canthen be etched with nitric acid to reveal beautiful Widmanstatten patterns. These patterns are never seen in terrestrial irons of any kind. Not all iron meteorites will show this; ataxites have no Widmanstattenpatterns. To get more geplicated there are different patterns seen with different classes ofIron meteorite.
Oriented meteorites show evidence of stability during flight with features resulting from the ablation process including flow lines as evidence of flow of melted material in one direction and a rollover lip on the trailing end; the overall shape of an oriented meteorite can vary a lot; its the lip and flow lines that are most convincing of true orientation. Oriented meteorites are often very pricey.
Among stony irons there are Pallasites and Mesosiderites. No pallasites are cheap, but some are very expensive. Unfortunately many are rusters. For my money Seymchan is the way to go; its is very pretty and does not rust easily, yet is still relatively affordable. Imilac and Esquel are beautiful and stable and also very expensive! A very thin section of Seymchan with lots of Olivine will be beautiful when back lit, and my favorite piece is also acid-etched revealing the Widmanstatten patterns as well. Buying a thinner piece will allow you to have a bigger surface area to display for less money in the long run, although thinner slices are more per gram in cost. Brahin and Brenham are also attractive, but can rust quickly in even a moderately moist climate. Beware though, even Imilac can rust if left in a humid environment!Don't keep your meteorites in ahumid part of your home like a basement or near a bathroom!
Mesosiderites are the other type of Stony Iron and look quite different. Outwardly they resemble a stone. The cut surface displays a lot of metal mixed in with the rock matrix.Technically they have about 50%metal which sets them apart from high-metal stones. Currently Vaca Muerta is the most reasonable mesosiderite for sale on okay; I regemend you get a nice one while you still can. Most mesosiderites are expensive, though nothing like the fancy pallasites.
Among stones, if you just want an example, you can get a nice unclassified NWA stone either as a whole individual, or an end-cut very cheap on okay. These unclassified stones are not very valuable and will not likely appreciate much in value, but they are a cheap and often attractive example of a stony meteorite. Expect to pay 10-20 cents a gram for a nice individual with fusion crust, or much less if you do not desire the crust; for me the crust makes a lot of difference because terrestrial rocks do not have a fusion crust and the crust sets the meteorites apart. On the other hand if you want a great stone meteorite with a lot of heritage and which is the source of some of the greatest discoveries in astronomy, get a nice example of Allende while they are still readily available. They will cost you $5-15 a gram but are fantastic meteorites with some of the earliest material of the solar system and even before it! This is still very cheap for a carbonaceous chondrite of this quality. A small individual and a slice or endcut will make a great display.
If you get more serious about your meteorites you can collect some of the more desirable examples; be prepared to pay a lot more for an ungemon meteorite. Be aware that in general, well-classified meteorites in a larger size with good display characteristics will both cost more and be a better investment, if you are concerned about that. In fact, some of the famous collections of meteorites like those of Haag or Schwabe (catalogs for sale on okay) are worth Millions of Dollars. It took many years of hard work, travel and investment for those guys to build those collections, so do not think meteorite collecting is going to make you rich (although it has for a few people like Haag; see the stories in the book mentioned above).
When expanding your collection be aware you will spend a lot more money on famous or important or rare meteorites. Although you can buy tiny "specks" of some the rare ones, you are better off in all ways in my opinion, in getting a specimen large enough to really enjoy, at least without much magnification. You might have to save your money to afford a bigger piece, but in the end you will be happier and have a better resale value too in case you ever want to or have to sell them. Lots of people will have a 100 gram Campo or a 20 gram Sikhote. Much fewer will have a multikilo piece. For some meteorites, 100 or 200 grams is large however. A 100 gram piece of a Martian or Lunar meteorite will cost you many thousands of dollars, so in some instances, a "bit" is all you will be able to afford.
Another interesting way to look at meteorites are microscope slide thin sections. These are also available from time to time on okay and cost from $10 to hundreds each, depending on the dealer and the sample. A thin section of a martian meteorite will cost you a lot more than a gemon H5 chondrite. To really appreciate these, they should be examined by polarized light; this is easy to do even without a petrographic microscope. Polarizing material is readily available for this purpose. I am an amateur, just like you and enjoy this as one of my hobbies; I seldom sell meteorites so I write this to help those of you interested in the hobby, not to help me make money. I hope this helps you and good luck in your quest.
Recently another book by Norton and Chitwood, Field Guide to Meteors and Meteorites has gee out. Like Rocks from Space, this is a must-have for any serious collector or even anyone interested in Meteorites.
A quick addendum on definitions:
Asteroid- large minor planet, most in orbit in the asteroid belt
Meteoroid-smaller part of an asteroid or planetwhich begees visible as a meteor when it heats up and glows as it enters the earth's atmosphere
Meteor- a visible trail of light as a meteroid or piece of a geetenters the earths atmosphere; note that geetary particles are rarely (if ever) recovered as meteorites as they are usually destroyed on entering the atmosphere
Meteorite- a recovered meteoritic mass on earth; once a meteoroid lands, by definition, its a meteorite
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