[meteorite-list] Point of Diminishing returns (Slice thickness)?

From: Adam Hupe <raremeteorites_at_meteoritecentral.com>
Date: Mon, 7 Mar 2011 15:38:25 -0800 (PST)
Message-ID: <361385.82499.qm_at_web30706.mail.mud.yahoo.com>

There is a point that a specimen will easily break if cut too thin. Some
material can be cut to 1mm thick but cutting losses can mount up to over 60%
even when using a wire saw after applying a polish. We had over 50% cutting loss
on Martian meteorite NWA 1195 which was cut on a diamond wafer saw and then
diamond lapped on both sides. I think a 2 to 2.5mm cut is reasonable on most
ultra rare material if polished on both sides. The thickness has to be greater
on friable material like Nakhlites otherwise you will receive a pile of crumbs.
It also has to be thicker on large specimens to support the weight on a display
easel.

Most collectors go by the price per gram first so dealers who cut ultra-thin
will take a loss when weight is the main consideration. I know that the
weight-to-surface area ratio is a secondary consideration for most collectors
due to experience.

There are other factors like a decent polish being applied, proper preparation
and specimen status including provenance that can affect price.


Best Regards,

Adam


 



----- Original Message ----
From: Richard Kowalski <damoclid at yahoo.com>
To: meteorite list <meteorite-list at meteoritecentral.com>
Sent: Mon, March 7, 2011 3:08:41 PM
Subject: [meteorite-list] Point of Diminishing returns (Slice thickness)?

These discussions about aesthetics of specimens vs their weight is rather
interesting, but it seems the lines of the subject are a bit blurred.

It seems the subject has come to comparing fragments to slices. I'm not sure
this is a fair comparison, but I understand it.

I am wondering what others think represents a point of diminishing returns in
making a slice paper thin. IOW at what point does cutting losses become too
great to make the aesthetic function of the prep & price excessive?

I guess I don't understand the desire for some ultra-thin prepped specimens. For
example, if a ultra-thin 1mm thick slice is being sold for the equivalent $80
per gram, and a slice of the exact same material, the exact same size, but 4
times the weight (4mm thick) is being offered at the exact same price, I'd be
inclined to purchase the latter.

I understand the appeal of of thinner specimens and of course you can polish a
slice so finely it becomes a thin section, but is there some point where the
prep becomes so costly that is is in fact "too thin" for the buyer?

Thanks

--
Richard Kowalski
Full Moon Photography
IMCA #1081
      
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Received on Mon 07 Mar 2011 06:38:25 PM PST