Tony Irving allowed me a look at his beautiful thin section of NWA 4905 and while I'm able to make layman observations of what I'm looking at, that is not helpful with such a subtly unique material. "It's beautiful!" but other than that, I'm over my head!

Nothing has been published yet (that I could find) so I posted the Meteorite List for help and Norbert Classen answered with a great description and a photo of his slice. There is really not much of this meteorite to go around. Chladni's Heirs list the TKW at just 36 g. so finding that Norbert had a slice was really cool!


Norbert Classen:

"When Martin Altmann of Chladni's Heirs first announced their new unbrecciated eucrite NWA 4905 on the MeteoriteCentral list he wrote: "It is an eucrite, full of sparkling grains of a mineral, which usually would let you throw a stone away as a terrestrial: quartz! Hence a so completely unusual material, that it's certainly worth to be venerated by the HED-lovers as a grail."

Of course, I had to get a sample of this unusual material, and I was glad to add a 2.3g full slice with dimensions of 32x24x1.5mm to my collection at last year's Ensisheim show. The photo doesn't do the sample justice - it's really full of sparkling grains - is it quartz or is it silica? The final write-up on this relatively coarse-grained, unbrecciated beauty hasn't been published, so far, and so I'm eagerly waiting for more news on this most thrilling find."

This is the photo of Norbert's slice. I'd like no know, how was this recognized as a meteorite in the first place? I think I would dismiss it as Granite.

This set of images starts with the thin section viewed in cross polarized light with no magnification and then zooms in with progressively higher magnifications. Starting with a Field of view at 4.40 mm up to 0.16 mm.

This set is taken with a field of view of 0.95mm. The shots break down like this:

1: plane polarized light
2: partially cross polarized light (-90 degrees)
3: fully cross polarized light
4: fully cross polarized light with a 1/4 wave retardation plate + 45 degrees
5: fully cross polarized light with a 1/4 wave retardation plate - 45 degrees



1: plane polarized light

2: partially cross polarized light (-90 degrees)

3: fully cross polarized light

4: fully cross polarized light with a 1/4 wave retardation plate + 45 degrees

5: fully cross polarized light with a 1/4 wave retardation plate - 45 degrees

My images are admittedly more art than science. I work in magnification levels higher than what is useful in classification and I add such things as wave plates to draw out more intense colors. I am amazed at the beauty every time I sit down to a new thin section but this time it really was fun.

Field of view 0.40 mm or approximately 160X (at the eyepiece).

Field of view 0.25 mm or approximately 400X (at the eyepiece).

These shots are my favorites. They are taken with an objective I just found. IT is DRY! An Apochromat 170 mm Leitz 40X with cover slip thickness correction that I have wanted for quite some time. My scope is 160mm but I have added so many filter holders (yes, more than one) and a magnification changer as well as a beam splitter all in the tube between the head and objective. While they all are corrected for a 160mm tube length, I find that the set up prefers 170 mm objectives. This narrows the choices!

Anyway, this is a field of view of 0.16 mm. The "At the eyepiece" magnification is 760 X but when 0.16 mm is projected to 30 cm on a standard size monitor the viewed magnification is 1875X. This is the best clarity I have yet achieved at this magnification. I have gone higher but with diminishing resolution.

Thanks for looking!

Tom Phillips can be reached by email at:/font>
STARSANDSCOPES@aol.com