How To Identify Extra-Terrestrial, Silicate (stony) Meteorites.

This page is updated and moved to  http://www.bccmeteorites.com/meteorite-identification.html

January 15, 2003, updated March 2004
by; S. Ray DeRusse, and see; Elements of Materials Science, Van Vlack and Cohen.

      This update is intended to help satisfy the natural curiosity humans have for the world and universe about us. I believe this may help bolster and to define the public's  natural curiosity about our surroundings. After reading hundreds of papers or perhaps thousands of pages of meteorite research and focusing on identification principles and methodologies, we come to several conclusions to help the public in it's own efforts of discovery and in applying necessary skills. Some of this new information is also for  those of you who have emailed us and are encountering problems in having found a possible meteorite but feel you are being given the run around by those scientists soliciting meteorite samples over the internet and then disappearing from the radar screen.
      Over many decades the overriding principle of  intellectual curiosity by your scientists on meteorites,  and their driving force appears to be a "highly unusual emphasis" on finding microbial life forms and water or water bearing mineralogy in meteorites. The abundant literature and research,  if it is to be taken as truthful or close to  factual, indicates that the aforementioned  are lacking in the samples studied over many decades. In addition to the first round of  elimination or inclusion pertaining to  geophysical characteristics used by many organizations and individuals, finding no fossil form of microbial life and no water or water bearing mineralogy in the sample may be an indicator the sample could be extra terrestrial. 
      This does not mean every sample lacking microbial life or water bearing mineralogy  is a meteorite. If the sample in your hand happens to meet the geophysical conditions of a meteorite, it just  means the terrestrial sample formed in highly reducing conditions of pressure and temperature. Forming oxides of  transitional metals, pure metals,  or oxides of semi-metals in crystalline silicate form as opposed to an amorphous form. There are many metallic oxides  and crystalline semi-metal oxides from Earth having no water or microbial life. The breaking down of semi-metal oxides and later forming concretions of  a variety of materials such as sandstone or metamorphic granitic material contain the water or microbial life we seek in meteorites. But these late stage terrestrial samples containing abundant fossilized microbial plant and animal life and water bearing mineralogy are not difficult to separate from stony meteorites found anywhere. This especially applies to stony meteorites which are at first  more difficult to isolate from  their terrestrial equivalents.
      The meteorites, of course, may contain this fossilized plant and animal microbial life.................. as contaminants. But this process of immediate contamination and later contaminating microbial plant and animal fossil material  is easily distinguishable from something formed in process. Lets turn the page and branch out in two directions and examine Lindstrom et al's "Pigeonholing Planetary Meteorites" paper,  and  isotopic analysis of meteorites. First of all, Lindstrom makes a good case that scientists misidentify meteorites because they pigeonhole them into known categories. This complaint is well founded and enigmatic behavior by the scientific community, and we think we found the root cause of it or at least one of the roots. If the stars are and the planets are lined up correctly for you, and a scientist wants to identify a meteorite, he or she readily finds a good fit or in the alternative depending on what's motivating them, creates a sub-subclass in which to fit it.  If he or she wants to exclude your sample mainly for political reasons it seems,  they begin to pigeonhole it in  a specific way in order to artificially create a failure through non- fit. This behavior has cost society dearly in time, money, and education and is an enigma in that it's very difficult to cleanse a criminal mind sprinkled with scientific misconduct as a safe harbor narrow mentality. Lindsrtom may not make much of an impact with this very important paper because a dismantling of  an entrenched elite culture rooted in racial bias and bigotry is necessary.
      Lets take a look at how a mechanism of isotopic analysis can be used in certain circles to pigeonhole and lead to misidentifying  samples, because this is very widespread in planetary science to maintain gate keeper status and elitist ownership of science.
   In lunar meteorites for example there is the persistent but bizarre claim that oxygen isotopic ratios and other elements must fall within a certain range or on a certain line.  The definition of ratio is: the relationship in quantity, amount, or size,  between two or more things.  In the literature, the word ratio is stretched and used very loosely because ratio implies an accurate counting. Since we are talking about atoms here it means someone has completely disaggregated an Apollo sample or a lunar meteorite and counted each atom of oxygen or other element to get an accurate (stable to isotopic ratio) count. It is easier to count oxygen because it is not an inert element. The problem with these bizarre claims by this small group of scientists is that it leaves them no wiggle room when new samples and new methods of  analysis are found or employed.
      The current suite of sample populations is so small and from a narrow compositional range resulting in closing the door with exact ratio claims would mean that the Moon formed in a literally closed system. Not affected by internal heating and magma diffusion to the surface, and meteorite impact both of which tend to change oxygen content over time,  and favorable to equilibrium of the local system. So if  a scientist tells you an element of anything or some other  isotope of an element from a meteorite must fall within a certain range or line, ask them to show you the data plots for the entire surface and subsurface of the planetary body or satellite in question. If they cannot fulfill this request then they cannot be taken seriously and they are wasting your time and everyone else's time. (The USGS has a nice handout on Isotopes).  It would be much more believable and reliable if the following has occurred  in lunar sample analysis. If the isotopic counting was tested on a one mile grid (or less) of  a cubic centimeter of the lunar surface, and then the same process was repeated taking a sample(s) from 25 meters beneath the surface at the same grid and once more at 100 meters beneath the surface. It's very unlikely that the isotopic ratio and counting for oxygen for instance, will fall on a straight line and the differences would be more indicative of the rock type coupled with the local geochemical process  in conjunction with lunar evolutionary history. It's highly  unlikely that oxygen isotope and isotopic counting in a high px breccia from 100 meters beneath the lunar surface is going to match the lunar regolith and or a differentiated surface maria basalt or anorthosite in isotopic content unit for unit. An exact match in oxygen isotopic ratio from these three differently formed provenances would be such an incredible coincidence, because that would mean that absolutely no internal or external disturbance ever occurred in and on the moon for billions of years after it formed, and that it formed under perfect conditions in an absolute vacuum.
      A mismatch from area to area would be more consistent with the data obtained from the Clementine data mission that indeed the Moon is much more varied in composition than previously realized.  This variation in composition (craters and central peaks to surface locally and regionally) has to extend from the macroscopic level to the atomic level. This conceptual notion of variation applies to any other planet in any other solar system in any other universe. A randomness principle for local planetary evolution and composition would revert ownership back to the planetary body. That is to say,  let the planetary body tell you what it is rather than the scientist forcing the planets and moons to be what he/she says. This behavior by our scientists, "it is what I say it is", is nothing more than injecting arrogance to fulfill some  human need of superiority. (see Angel Speck, "let the planetary body tell you what it is").
     One way to start  getting back on track with M. M. Lindstrom is to  stop creating cutesy bizarre little names, hence whole branching out sub-classes of rock types just because a single stone or breccia contains an inclusion or crystal of say hematite (for instance). Some meteorite rock types we have seen have been given entire subclass or sub-subclass branching direction names for a single crystal which is rather a bizarre notion because as we see it,  the scientific community is entangling  itself  in unnecessary branches of rock types and classes. This bizarre naming of an entire subclass for a  single inclusion means there is an infinite possibility of rock types for one planetary body and See, "Proceedings of the Conference on the Lunar Highlands Crust" , Houston, TX, Nov. 14-16, 1979 page 51.
      Here are some uses of common isotopes. Bone recovered from archaeological sites can be analyzed isotopically for information regarding diet and migration. Carbon and nitrogen isotopic signatures are used to reconstruct diet, and oxygen isotopes are used to determine geographic location. (Not to pigeonhole meteorites nor classify entire planets and satellites and artificially include or eliminate new samples). In planetary science, isotopic composition should be more closely tied to rock - region  type. So if you have two different rock types from the same body,  the likelihood that they are going to contain the exact same quantity (count ratio)  of 16O , 17O and 18O  is far fetched. If  a scientist wants to claim a fixed ratio for an entire planet or satellite then he or she must be advancing the notion that it only contains one rock type and formed and evolved in a closed system since the beginning of time. On the other hand, if they want the public  to recognize many rock types from a single planet or satellite,  then that scientist needs to be prepared for chemical ratio-variation at the atomic level hence nuclear isotopic level from region to region, central core to surface in all directions.

In making a qualitative statement presented as factual, a scientist must have done the required wide range of sample population testing in order to support this statement. For instance, a statement that x-y elements and isotopes must fall within a defined range for an entire planetary body is a qualitative statement that essentially closes the door on new discoveries or deviated findings. This kind of statement cannot be made unless the sample population of materials tested is of sufficient quantity to account for the broadest range of possibilities. In other words samples must be obtained from the entire body be it venus, the moon or mars. If the sample is restricted in compositional range or population too small there will  be the narrowest clustering of data so as to make the results unreliable, and  therefore  the statement can  be no more than a  prediction  but certainly not  a factual statement. See also Tom van Flandern, "Are The Mars Meteorites Really From Mars?"

delving deeper

      We have always had the gnawing feeling that something was amiss in the theory that the Moon is a remnant product of the collision between a mars size planet and the Earth. The reason for this is that if indeed this occurred there should be some fossilized microbial animal or plant life found in the Apollo samples. Several days ago, an announcement was made that microbial fossil life had been found in a rock from Earth three billion years old. The Earth is a much more active geological body than the Moon therefore these microbial life forms should be very easily found in lunar samples. None has been found that we know of,  so this impact theory is just so far out there it never happened. Second,  certain scientists have often indicated that once a theory is bought into by the community at large, the scientific work and research is geared and formulated to patch up the theory and make it sustainable. It appears that much of the research we have read on lunar sample analysis does just exactly that.
 

    This web site deals primarily with the samples found in Boggy Creek in Central Texas. To our knowledge, the two classes of Meteorites known as Irons and Stony irons have not been found in that body of water and that locale. Therefore we deal only with Stony and Anomalous samples found by us. We would like to comment on "Iron Meteorites",  (below), because there is the misconception that Iron Meteorites exist in greater numbers on the surface of the Earth. In fact, the inability of many in the scientific community to distinguish stony meteorites from terrestrial material in a temperate climate makes it difficult to find and identify new samples and broaden our knowledge based on new samples.  Many rare and unusual samples are being overlooked. Stony Meteorites are much more durable and plentiful than Fe-Ni samples but again, because of their appearance, less easily recognizable. The Achondrite class have a remarkable appearance to ordinary terrestrial basalts and from the literature, many lunar samples appear brecciated containing clastic features. (gray with white, gray white clasts). Heavily weathered stony meteorites tend to resemble terrestrial rocks as in the BC Collection. Regmaglypts (thumb print indentations) will not be found on the surface of weathered stony meteorites because they do not generally have enough metal to induce a melting and pitting on the surface. Silicate samples will generally have a more compact ground mass than [equivalent] terrestrial samples, be slightly to highly magnetic, may or may not contain a fusion crust, unless broken will generally be flight oriented, (elongated and or pyramidal shaped), with rounded corners, and may or may not contain microscopic inclusions of metals and/or silicate crystals and anomalous inclusions, (depending on its evolved state and origin). An interesting note here is Robert Bauval (a Belgian scientist) theorized the Egyptians patterned the pyramid structural shape after meteorites because they noticed that the stones raining from the sky and found on the desert floor were generally 3-4 sided having a base and reasoned that this must be the proper shape most durable in high desert winds.

    1) First of all there is no such thing as purely-Iron Meteorites because pure Iron does not exist in nature. "Iron Meteorites",  are composed of a small percentage of Fe mixed with a large percentage of Ni and thus are composed predominately of the element Ni with varying amount of Fe

    2) Stony Meteorites are composed of a solution of Si and O and contain a definite proportion of Alkali, Alkali Earth, and Transitional metals within the crystal structure at the cell level. Trace elements, isotopes, halogens, and inert elements are also found in meteorites.

    3) In "An Introduction to Meteorites", linked at the bottom of this page, Dr. Angela Speck writes,  "A more useful categorization, rather than one dependent on appearance or bulk composition of the meteorites, is based on their history or that of their parent bodies (the asteroids and/or comets of which the meteorites are fragments)." We could not agree more and this is what we are aiming for in identification of our samples. But this is very difficult for us not having the proper facilitates and instrumentation on site. See Lindstrom et al. on Misidentification of Planetary Meteorites. Lindstrom is mentioned here because misidentification is more than likely a very common problem, sometimes accidental but sometimes intentional. We have evidence of intentional misidentification of samples by Geologists so this is nothing new to us.
    However, if the reader just wants to identify a sample as terrestrial or non-terrestrial then bulk composition and inclusion analysis is sufficient with inclusion analysis not being absolutely necessary. Unusually close matches to "reliable existing data",  can be a good clue as to the sample authenticity.  Identification can be accomplished by several mechanisms including conducting XRD in a laboratory, because one can obtain the major and minor phases present in the sample. For instance, XRD analysis of BCC9601 (Lunar), indicates a bulk composition of  a) (Na,Ca)Al(Si,Al)3O8 "calcian-ordered" and b) Na(AlSi3O8) Albite low, and c) MgSiO3 Protoenstatite, and d) Quartz alpha, SiO2  e) "synthetic".

lunar meteorite
BCC9601, Lunar highlands surface plagiocalse feldspar. Complete differentiated solid solution.  See man made lunar regolith or pure lunar dust made from crushing a piece of this sample.

Interpretation of the XRD data and results is very important and is as follows. Note that,  preliminary and final analysis provided by AMIA consists
of bulk phase composition. Several sections and one fragment  were used for three XRDs to determine extent of homogeneity across the sample.

    a) The first part indicates the sample is a complete solid solution of plagioclase feldspar. The "[calcian ordered]" is long hand for anorthite/anorthosite. Anorthite from the Moon is very different from that found on Earth. The reason it is indicated as "calcian ordered" is because pure Anorthosite is so rare it is not in the XRD database where the sample was analyzed, even though the data base contains some 80,000 formulas. Calcian ordered also satisfies Paulings Rules for atomic size, combined with charge balancing for the crystallographic makeup and complete solid solution of the sample. This tells us this sample is a high temperature melt.
    b) The second part indicates that the solid solution continued up until cooling and crystallization and the substitution continued with [NaSi] replacing [CaAl] making the sample more Sodic. [Almost equal Na-Ca with high K, Al, and SiO2 at differentiation, with low Ti and Fe], indicating a surface crustal floatation magma.
    c) In part 3 the MgSiO3 is a stellar grain of Enstatite we intentionally bombarded with X-Rays and picked up by the Diffractometer detector. BCC9601 has many stellar grains of various composition.
   d) The SiO2 indicates the sample has an overabundance of silica in solution, and some of it is out of solution uniformly distributed through out the ground mass as a quartz material. If the sample is surface crustal material it should contain approximately 1/3 more SiO weight percent than subcrustal (non- floatation) material. The alpha quartz indicates the sample tested was undergoing a reconstructive transformation from Cristobalite-Tridymite to stable quartz, but this occurred for approximately ~1, 1-1/2  cm inwards from the outside of the sample. This transformation at the out side edge of the sample is distinctly noticeable from the inner material.
    e) The "synthetic" wording: PDF match. (low level impurities yields crystallographic data refined from Syn, Pdf  single crystal-peak and constants match),  indicates that the SiO2 bond lengths and angles are highly distorted, produced in a high T (>1600c), P (>10 atm vac P) environment. Hence the "synthetic" designation is analogous to "laboratory like" conditions.  and Everything taken together including an anhydrous sample, having a very specific ratio of TiO2-FeO [~1 : 10], and ~10% Al2O3, by EDS analysis, points to a differentiated Lunar Highlands surface crustal origin for the sample. It should be mentioned here that this sample cannot be produced nor reproduced in a laboratory!
The final major-minor phase separation was completed and the sample is consistent with a differentiated lunar surface crust.

      
    Why are Stony Meteorites so durable in a variety of environments on Earth. The answer is to find out what it takes to decompose the sample in question by various chemical processes. Special attention to the slow decomposition of Stony Meteorites should be paid to their initial environment history of cooling and crystallization. (Temperature, Pressure, and volatile content during formation). The decomposition rate for the BCC samples or any meteorite for that matter, can be found at the lattice level. There must be sufficient site dislocations and missing occupancies within the crystal structure for a chemical reaction to readily occur and decomposition to begin. There must be a mechanism for the sample to be attacked in an ambient environment. If there is no opportunity or the temperature surrounding the sample cannot be sufficiently raised to dislocate lattice site occupancies and break the atomic bonds, then natural decomposition
 can take millions of years at standard conditions in an ambient environment.  Below are some rules that apply to matter in achieving equilibrium in standard
 conditions.


CORROSION:

    CORROSION BY SOLUTION.  The following generalizations may be made about chemical solution :

    (1) Small molecules and ions dissolve most readily. The simplest corrosion is by chemical solution. The components of asphalt, will dissolve more readily than the components of a highly polymerized plastic. Apparent exceptions are polymers which are easily depolymerized, but here the material goes into solution as small molecules. Similarly, alkali and halide ions have greater solubility than more complex silicate ions.

    (2) Solution occurs more readily when the solvent and solute are structurally similar.  Organic materials are most soluble in organic solvents, metals in other metal liquids, and ceramic materials in other ceramic melts. Even within these general categories, a similarity of solvent and solute structures produces greater solubility. For example, polyethylene is more soluble in liquid hydrocarbons than in liquid phenol, and copper is more soluble in liquid zinc than in liquid lead.

    (3) The presence of two solutes may produce greater solubility than the presence of only one. As an example, the calcium carbonate (CaCO3) of limestone is nearly insoluble in pure water. However, the addition of CO2 to form carbonic acid in the water markedly increases the CaCO3 solubility. Limestone caverns are the result of the dissolution of CaCO3 by water containing organic material. The time required for solution in this case is exceedingly long, of course, but the same effect occurs when limestones, or calcium carbonate bonded sandstones, are used for construction materials in an industrial atmosphere containing such gases as SO3. The solution of SO3 in atmospheric moisture produces a dilute sulfuric acid solvent which will react directly with CaCO3.

(4) The rate of solution increases with temperature.  Solution involves diffusion, and since diffusion occurs more rapidly with the greater thermal vibrations at higher temperatures, solution corrosion will also occur more rapidly with a rise in temperature.

OXIDATION: "Iron Meteorites, and Fe in silicate meteorites"

    (5) Corrosion by Oxidation. Direct oxidation that results in the formation of an oxide scale occurs more readily at high temperatures. However, strictly speaking, oxidation is the removal of electrons from an atom, and therefore it may involve the formation of numerous types of reaction products. For example,[ Fe---->Fe++ plus 2e-], is the expression for the oxidation of iron into ferrous ions, and [Fe++---->Fe+++ plus e-] is the expression for the oxidation of ferrous ions into ferric ions. These reactions are most common in rust formation. Rust is ferric hydroxide, and is formed according to the reaction, 4Fe+3O2+6H2O---->4Fe(OH)3.
    For iron to rust, both oxygen and moisture must be present. Iron will not rust if it is submerged in oxygen free water, nor will it rust in an atmosphere containing only oxygen. However, in practice the amount of moisture required to produce the above reaction may be surprisingly small. For example, the moisture content of the air can quickly produce rust on hand tools in a basement.
    Different metals have different oxidation potentials, inasmuch as the energy required to remove an electron varies from metal to metal. Electrons are more readily removed  in some environments than others. For example, electrons are removed from iron when oxygen and water are both present, and they are more easily removed from aluminum atoms when chloride ions are present. The oxidation on the surface of "iron" and stony meteorites is readily apparent however, and more importantly, the extent of the oxidation is proportional to the opportunity presented by the geophysical and chemical characteristics present in the sample. Usually the rate will be very slow and cease at a certain point on the sample unless there is a drastic change in the environmental conditions, such as a noticeable upward change in the ambient temperature conditions.
    In short, if left undisturbed in ambient conditions, any meteorite should be expected to alter slowly and survive for millions of years.

Additional Resources For Meteorite Identification We Highly Recommend.

    The Dutch Meteor Society has an excellent detailed primer on Meteorite Identification, and Dr. Angela Speck has been nice to loan us her Meteorite Introduction Page. (Dr. Speck has devoted much of her web pages to her research and educational materials and anyone interested in astromineralogy will be dazzled by her and her colleague's work, please visit her site). See also the following page for meteorite appearance by answering meteorite dealers question.