Mike,

I studied your sample with the electron microprobe, using what is called

EDS analysis. This is a semi-quantitative method for identifying

individual mineral phases by their elemental spectra. Your sample

contains small grains of feldspar, quartz and magnetite. The bulk

composition is fairly high in silica, with lesser amounts of aluminum,

calcium, sodium, potassium and iron. Texturally and compositionally, it

appears to be a high-silica volcanic rock, most likely a rhyolite. Since

rhyolitic volcanic rock is not uncommon to your area of Texas and New

Mexico, I would suggest that you try to find a connection with a nearby

volcanic field. You now have plenty of data to do this. This may not be

your preferred explanation for the origin of your rock, but all

possibilities must be considered. We have found nothing about the sample

to suggest that it is meteoritic, although we are certainly not

discouraging you from performing more tests. At this point, any more work

that we do would require much more expensive and time-consuming tests,

which we reserve for our own research program and the occasional sample

that we have determined to be a meteorite based on other evidence.

I also took the liberty of putting the large sample you sent me into an

ultrasonic bath to extract the interior particles. They mostly appear to

be sand-sized particles derived from the rock itself.

If you are still convinced that this rock was blasted off another large

planet, you would have to demonstrate that it has internal shock

deformation. We did not see evidence for this in thin section. The

scoriaceous texture of the rock makes it an unlikely candidate to have

survived such an event. Much more likely is that it was recently eroded

out of an outcropping of volcanic rock not too far from where you found

it. It may be possible that a rock this light could have been partly

transported by wind, as well as running water. Some of the particles

inside the cavities may also have been deposited by wind.

I don't mean to disappoint you with our interpretation, but I cannot see

being able to justify any more tests on this sample by our lab. If you

want to pursue it further, there is one more thing you can do. A

commercial laboratory will also perform neutron activation analyses for

$100 or so, which will get you high-precision trace element data. The key

elements for extra-terrestrial comparisons would be elements like Fe, Mn,

Al, Ga, K, La. If you decide to do this, I would still be happy to go

over the data with you. Chemex labs should be able to do this kind of

analysis.

Thanks for your efforts. We admire your persistence, and I'm sorry we

can't be more optimistic about the origin of your rock. I'll be happy to

return any sample that you sent us, just let me know if you want it back.

Best regards,

Jamie

****************************************************************

James D. Gleason

Lunar and Planetary Laboratory

University of Arizona

Tucson, AZ 85721

(520) 621-7984 (phone)

(520) 621-6783 (fax)

jgleason@gamma1.LPL.arizona.edu