[meteorite-list] Proposal: Joe Six Pack's Weathering Scale

From: Martin Altmann <Altmann_at_meteoritecentral.com>
Date: Wed Nov 2 12:25:42 2005
Message-ID: <008601c5dfd4$23f44900$6389fea9_at_9y6y40j>

One can't determine, but one can guess macroscopically
and if one has had a lot of stones in one's hand,
the later correct determination of the weathering degree, often is as
supposed :-)

Let's be constru- and instructive, that's what the list is for, and try to
built up together a scale for rough estimating without a microscope:

JSP - weathering scale (provisional)

W0 -
Black, dull fusion crust of silky to rough appearence. (or glossy shiny if
basaltic).
No stainings on the crust, if exist hairfine flightmarks.
If a fragment, sharpest edges, many different tiny "things" visible on the
broken surfaces, broken surfaces crumbly.
All what looks like metal has no brown rims around. No brown mottling after
cut.
Little Devil on shoulder says: "You MUST have it".

W1 -
Still black fusion crust, but shiny and smooth, like a little polished. Some
smaller brown areas on the crust possible, also metal grains lurking through
the crust.
interior and crust easy distingushable; side where it sat on the ground of a
different color; little brown auras around metal grains.
Cut surface some brown mottling. Nothing red inside. Nice, nice

W2 -
Remainders of fusion crust, looking quite thick, shiny and not black
anymore. Fractured edges rounded. Fractured surfaces shiny and smoothened.
Pit's from chondrules visible there. Major parts of cut surfaces brown. Dirt
on bottom. Flight marks gone.

W3 -
No crust, rounded, desert varnish, light coloured caliche, where it was in
ground. Cracks possible. No tiny regmaglyptes visible. If cut, iside of more
or less uniform brown colour. If fragment, broken surfaces look like
undamaged parts.
To say it short, that stuff, which you find most, if you're wandering around
on a large fair and which let you shrug your shoulders.
Reads on ebay: "beautiful stone"

W4 -
Like W3, but also often with deep cracks and clefts with rounded edge,
sometimes caliche inside or even tiny stones. Cut boring brown, with
sometimes some snot - People will say "I bought it from Bessey" (nooo, just
a jokus, he has a lot of fine stones tooo).
Reads on ebay "nice stone"

W5 -
You can break it up with one hand.
Reads on ebay "inetersting shape"

Let's work it out - more suggestions?
Buckleboo!
Martin

----- Original Message -----
From: "Jeff Grossman" <jgrossman_at_usgs.gov>
To: <meteorite-list_at_meteoritecentral.com>
Sent: Wednesday, November 02, 2005 4:51 PM
Subject: Re: [meteorite-list] New Lunar Meteorite Discovered - NWA 3163


Just out of curiosity, how can you determine the
weathering level of a meteorite like this, which
lacks significant metal and sulfide? The scale
up to W4 is defined by these and only these minerals:

>W0: No visible oxidation of metal or sulfide. A
>limonitic staining may be noticeable in transmitted light.
>W1: Minor oxide rims around metal and troilite; minor oxide veins.
>W2: Moderate oxidation of metal, about 20-60% being affected.
>W3: Heavy oxidation of metal and troilite, 60-95% being replaced.
>W4: Complete (>95%) oxidation of metal and troilite.

jeff

At 10:33 AM 11/2/2005, Greg Hupe wrote:
>Hi Martin and list,
>
>The scientists believe the terrestrial age of
>the new lunar, NWA 3163, will show to be very
>low as to the lack of weathering, which he
>states is most likely a weathering level of W1.
>Results will be forthcoming and I will share the
>new data as it becomes available.
>
>Best regards,
>Greg
Received on Wed 02 Nov 2005 12:37:46 PM PST