Conducted by Ron Hartman
Department of Earth Sciences & Astronomy
Mt. San Antonio College
Starting and Maintaining Your Meteorite Collection
Fourth in a series of introductory topics for the beginning meteorite collector!
The focus of a collection can have as many directions as there are collectors. To answer a question or solve a problem, a collector can obtain information almost immediately from very qualified fellow collectors and dealers, thanks to the venue of the worldwide Internet. Many serious collectors pride themselves in having websites that offer an extensive amount of information, photographs of different kinds of meteorites and links to almost anything one would want to find. Research institutions, such as U.C.L.A. and U. of A., offer helpful websites. See:
http://www.ess.ucla.edu/research/cosmochem/meteorite.asp http://geology.asu.edu/research/meteorites/meteorites.html, and http://seds.lpl.arizona.edu/nineplanets/nineplanets/meteorites.html. There are many more.
David Weir’s website is a MUST for general background information, at: www.geocities.com/CapeCanaveral/9278/. Commercial dealers, such a The Meteorite Market www.alaska.net/~meteor/type.htm, and Eduardo’s meteorites.com website (www.meteorites.com/classif.html) display comprehensive lists showing the classification of meteorites. A search engine such as Google will provide many more.
We are often asked. “How do I get started and what do I do?” I’ll try to address those questions now.
CRITERIA FOR SELECTION
Some of the specialized criteria collectors May use for selecting specimens include one or more of the following:
a. Collecting only observed falls (such as Portales Valley, Holbrook, Allende)
b. Collecting by name of the meteorite (including historical falls, such as Mocs, Wold Cottage, and Ensisheim.)
c. Collecting by classification (examples of the many classes, weathering grades and shock stage.)
d. Collecting micros (under 1 g). and macros (a few grams) [a very cost-effective decision]
e. Collecting thin-sections
When one collects, he/she should have a plan, or focus. Otherwise, the collection will end up being a very expensive hodge-podge of miscellaneous pieces and fragments, which May result in not a very meaningful or useful collection.
CRITERIA FOR VALUE
A collection will begin small, but for some collectors, what May follow sometimes becomes even worse that the plight of the compulsive gambler! What starts in all innocence can easily get out of hand as quickly as a wildfire in a strong wind on a hot day! Let me quote from just a few emails received from clients (no names):
“Can you hold my specimen until my food stamps arrive”
“I’d like to order your…oh d – – -, here comes my wife! Never mind”
“I’ve just purchased my first meteorite. I think I am getting the “bug”!
The point is that eventually a bit of change will be invested. And, at some point the collector May want (or need) to sell, trade-up, or exchange specimens, so it is well to buy wisely and document each purchase.
Rule 1 “No impulse buying”. Know your meteorite.
Shop several sources, not only for price but also for quality of the piece. Cut specimens should be nicely prepared. Slices and slabs should be flat on both sides with sides’ parallel [not wedges], no broken corners, and properly ground and polished to best show structure. Pieces should maintain the integrity of the flat surface right to the edge, with no turned down (curved) edge (poor polishing technique will cause this). Irons must be properly stabilized and, if required, coated, and guaranteed not to rust for a reasonable period of time.
Keep in mind that it is not how highly polished the meteorite might be, but whether it is ground and/or polished to the point that its structure is best seen. We recently received a small Allende which could hardly be recognized. The cut surface was so highly polished it was featureless. Roughing it up to #600 on the lap machine brought out a wealth of detail.
DaG 749 CO3 (as in the above picture) can show very nice sharp chondrules if ground to around #400 on the lap machine. With finer polishing the features disappear. There really is no rule. Each meteorite requires that it be uniquely prepared to provide an optimum of visible structures.
Irons, especially large slices, ideally, are ground and etched on both sides. After all, you are paying by the gram. If only one side is etched you can see only half of what the specimen May otherwise reveal. You have lost one half of the science. Be sure the iron is flat (use a straightedge), not warped or with a curvature, nor wedge shaped. No rust should show and there should be a warranty that the meteorite won’t rust a week after you purchase it. A dealer should be able to offer a service to repair a specimen if there is any rusting soon after a purchase is made. If there is a charge, it should be reasonable if rust does appear within a short time. (Yes, we all agree that there are trouble spots in the world where the collector May live in humid or otherwise unsatisfactory conditions where it is difficult to prevent even the best of irons from rusting. It is also the responsibility of the collector to know how to provide a dry and safe environment. A tight case or jar with a desiccant (silica gel or activated clay both work well) and a humidity indicator (card or inexpensive hygrometer) that reads levels down to at least 30% works well.
Prices fluctuate wildly over even short intervals of time. It is common for a new and sough-after meteorite to appear one year, flood the trade-shows, and then become virtually non-existent two or three years later. The price then goes up. On the other hand, if a small amount of a new meteorite appears, then at a later date, much more of it comes to market, the price May drop dramatically. This is why one should shop for quality and importance of a piece, not only a name.
Rule 2: Know your source.
There are many look-alikes, and many meteorwrongs posing as meteorites appearing on auction sites. You want to be sure that your purchase is what your label or Certificate of Authenticity says it is. Your last line of defense here is the reputability of the source. A known and respected seller, whether a commercial dealer, or large collector using a web or auction site, will be happy to document his/her sources and provide a guarantee of authenticity.
Rule 3: Create a manageable inventory scheme and determine a safe way to archive your collection.
Not only for your own use, but because of possible trades or exchanges later on, some of which May carry tax-consequences if there are profits, you need to retain:
a. A sales receipt or at least a copy of correspondence describing the purchase along with your cancelled check.
b. A picture of your specimen with a coin or rule showing scale. Digital cameras are very useful and it is inexpensive and easy to maintain an electronic photo-album. Be sure to have close-up capability.
c. An inventory list you can keep in tabular form. (You May want to devise your own scheme to keep track of your specimens, especially if you have more than one of a specific meteorite. Software, such as Microsoft Word™, is useful. I like “Word” because it is easy to use, with an almost instant learning curve for setting up a table. I have my collection set up with columns for name of meteorite, date of purchase, my cost, source, my inventory number, classification, weight, and drawer location. It is possible to rearrange a list by any of the aforementioned parameters with the click of a button. Be sure to have a backup and a paper printout as well.
Many old collections, especially museum collections, include a specimen number printed on the side of the specimen. This is usually done using white enamel and India ink. I have done this with a number of Irons that I found some 40 years ago and the identification marks are holding up well. However, I prefer not to put markings on specimens now, but rather to use the methods discussed here (photo, dimensions, and weight). If you are identifying a specimen by weight, I suggest using a quality digital scales that gives an accurate reading to at least two decimal places, and for micros, to four places. For smaller pieces, I use an Acculab V-200 with a capacity of 200 g. and an Acculab Model LA-110 electronic digital scale with a capacity of 110 g. and an accuracy of +/- 0.0001 g. for macros and micros. I realize that a quality scales is expensive, but it is an investment that over time will prove to be quite valuable. [I mention these models as examples because I have found them to be quite cost-effective and very dependable. There are many such products on the market. Shop discount websites for very good prices. They are there!
CRITERIA FOR ARCHIVING
Ideally you want a case with automated humidity control. And for thousands of dollars this can be had. However, for most of us this is not affordable. The next best thing is to find the best possible way to protect a specimen, whether stone or iron, from excessive humidity and heat. It is the presence of humidity and heat in stagnant air that causes problems. Iron meteorites and some pallasites can be the most troublesome. Some, but not all, stones, can also be subject to rusting.
There are several culprits that May contribute to rust. One is moisture that soaks into the fissures or around structures such as the inclusions in irons. (Is your meteorite properly cut and stabilized, with all traces of water removed from these interior spots?) You will find out shortly after you purchase your meteorite! Another is moisture that is simply in the air around your meteorite. This becomes most troublesome during hot, humid summer months. The third is chlorine, which has penetrated an iron, or even a stone, while buried in the ground. When cut, the newly exposed surface comes into contact with oxygen and moisture. Small yellow or green droplets (like drops of honey) May begin to ooze from the specimen. Nantan is an excellent example of this. (Just think, how May rocks have you seen that ooze a sticky liquid!) Left unattended, ferrous chloride, FeCl2 (the droplets) will oxidize in air to form FeCl3 , causing rusting and pitting of the iron. An immediate solution would be to quickly blot these droplets dry and dab a bit of alcohol on the region to eliminate any residue. If such a specimen is thusly maintained, it can usually be an enjoyable and lasting addition to a collection.
Here’s something I recently did in my office. I took four shelves at eye level in a wall to wall bookcase and turned them into four small display cases. The sides are sealed and there is a plate glass front that seals tightly around the edges with weather-stripping. Silica gel is used inside, and there is a digital humidity gage to check humidity. Although the location is a NE corner of the building with much shade outside, fluorescent lights (which are left on 24 hr/day) seem to provide a stable temperature of around 80 degrees, regardless of room conditions. Humidity is maintained at around 45%; not ideal, but acceptable.
A container should be tight. There are many brands of small plastic boxes that are both inexpensive and tight. Riker ™-type cases provide an attractive way to display pieces and are inexpensive. (Available from www.jensenmeteorites.com) They keep a specimen dust-free and away from fingers. I use them extensively in our museum collection for display. They are not airtight or moisture proof, though. We have noted that Irons should be rotated occasionally as moisture builds up on the backside in the padding and eventually May encourage rusting.
The newest idea to come along are membrane suspension boxes. These plastic containers seem to be reasonably tight (especially the small micro boxes). They have two invisible plastic membranes that come together when the box is closed. When the specimen is sandwiched between them it is held tightly suspended inside the case, providing protection from the outside world. Both front and back of the specimen, and the sides, can be viewed without opening the box. Like the Riker’s, they come in several sizes. (Two sources for these: www.meteorites.com or www.membranebox.com.)
Some collectors have kept irons in jars filled with anhydrous alcohol to protect from rusting. We discourage this as we have seen that it appears not to work. If any water is absorbed by the alcohol (and you May not be aware of this), you have invited disaster.
Finally, like anything else, proper long-term maintenance of a collection is necessary. More on this, including cutting, polishing and etching next time.