[Avodah] kashering caeser stone

[Daniel Israel]

On Mon, 23 Apr 2007 20:21:15 +0000 Micha Berger <micha at aishdas.org> 
wrote:
>I was contacted off list by someone who knows the subject.
>
>Alloys and chemical compounds aren't mixtures in the same sense as 
a
>mixture of powders, air, or caesar stone. Caesar stone isn't a
>combination of chemicals to make a new chemical, but a collection 
>of disparate things in mixture. There is a difference between a 
gas 
>which contains a mix of oxygen molecules and hydrogen molecules, 
and 
>water.
>An alloy like steel or 14K gold would be a single chemical.

I'm pretty sure that this is not quite correct.  Alloys are in some 
ways more like mixtures than compounds.  In a chemical compound the 
various elements combine into molecules at the atomic level.  In 
your example, a molecule of water contains two hydrogen and one 
oxygen atom which are bound together by intramolecular forces.

Alloys, such as steel or 14K gold, are made up of grains, and each 
grain is a crystal containing only one element.  The size of the 
grains may vary depending on how the alloy was produced.

Things like ceasarstone are made from separate pieces of stone held 
together by a resin.

Of course the pieces in ceasarstone are much, much bigger than the 
grains in an alloy.  Also, the grains are held together by chemical 
bonds, not by some type of glue (resin).

Hope that's reasonably clear.

--
Daniel M. Israel
dmi1 at cornell.edu