[meteorite-list] Micromounts and weights - Standards Vary
From: Michael Gilmer <meteoritemike_at_meteoritecentral.com>
Date: Thu, 30 Jun 2011 19:16:31 -0400 Message-ID: <BANLkTimJ-T6t3dcgd-zrPO-sn=SNuTVNsg_at_mail.gmail.com> Hi Listees and Micronauts, There has been some discussion recently about people buying micromounts from a vendor on eBay and not getting the weights they were promised. I thought I would throw out some thoughts on micros, since those are my bread and butter. First, the definition of "micromount" is relative. There is no set-in-stone size bracket for what defines a micromount. It seems to me that the general consensus is that micromounts are in the 1g range for the more common types and sub-gram in weight for the rare types. Very rare falls or planetaries are commonly sold by the milligram. Rockhounds tend to equate meteorite micromounts with mineral thumbnails. But generally speaking, most micromounts on the market today are in the sub-gram (<1g) range. Ideally, a micromount should be visually appealing (such a well polished, thin part slice with good surface area to weight ratio) and big enough to identify the lithology of the type/fall, while at the same time being cheap enough to afford on a limited budget. The more preparation that goes into making a given micromount, the higher the price, generally speaking. At some point, it's not financially viable to put a lot of cutting and polishing work into piece of common find that is only worth a buck or two a gram. Smaller micros are difficult to work with during preparation, for obvious reasons, so many of the micromounts seen on the market are unpolished, rough, or broken. What motivates a person to collect micromounts varies from person to person, but the most commonly cited reason for buying micros is to temporarily fill a void in a type collection. It could be a petrologic type, a find from a given geographic area, a fall from a specific date, etc. Often a micromount is a temporary measure until a nicer specimen can be acquired, or until the needed finances to buy a larger piece can be saved up. For the very rare types and planetaries, a micromount might be the best hope for a collector on a restricted budget. There are a couple of schools of thought when it comes to dealing and selling micromounts - some dealers sell specimens by weight (by milligram, even for specks) or some dealers offer specimens by the piece (by eye/photo). For the most part, I am of the latter school that sells micros by the piece. That means I don't weigh each and every micromount, unless it is a very rare and valuable meteorite such as a planetary or historical fall. Each dealer has their own methods for handling micromounts and we those aren't really relevant to the discussion at hand. When weighing micromounts, one must use an accurate scale that is sensitive to 1 milligram - the good ones are used by diamond and gem dealers. There are many brands of these scales which range in quality and accuracy. When dealing with small specks that weigh a milligram or two, the readings can vary from unit to unit when weighing the same specimen. If a buyer pays for and is promised a micro that weighs 100mg, it better weigh 100mg and not 50mg or 80mg. Sometimes a buyer gets an added bonus because their personal scale is more accurate than the seller's scale and a promised 100mg micro might weigh 120mg or 150mg. If the seller is not sticking to a strict pricing scheme ($/g or $/mg), then ultimately what matters is if the buyer is happy with their micromount. >From a collector's standpoint, it pays to shop around for micromounts. Unless it's a very rare meteorite, it's easy to find several dealers offering similar-sized specimens for widely-varying prices. One must also pay close attention to the reputation of the seller and the provenance of rare specimens. Because micros tend to be small (some are downright tiny), it would be easy for an unscrupulous seller to misrepresent specimens as something more valuable than what they truly are. Chances are, if you are reading this mailing list, you are one of those people who can find a reputable source and who does their homework before sending payments across oceans on fiber-optic cables. My own personal meteorite collection (the pieces I keep in my cabinet and are not traded on my website) are mostly micromounts and I keep the majority of them stored in 1.25" gemjars with paper labels inside the bottom, under the foam. Some people prefer membrane boxes, small Riker boxes, or other storage and display methods, but that is the subject of an entire debate of it's own. The most commonly-seen container on the micromount market is the gemjar, and thus it is a general rule of thumb that if a specimen will fit into a gemjar, then that specimen could/should be called a "micromount". Best micro-regards, MikeG -- --------------------------------------------------------------------------------- Galactic Stone & Ironworks - Meteorites & Amber (Michael Gilmer) Website - http://www.galactic-stone.com Facebook - http://tinyurl.com/42h79my News Feed - http://www.galactic-stone.com/rss/126516 Twitter - http://twitter.com/galacticstone EOM - http://www.encyclopedia-of-meteorites.com/collection.aspx?id=1564 ---------------------------------------------------------------------------------Received on Thu 30 Jun 2011 07:16:31 PM PDT |
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