[meteorite-list] mafic igneous rocks
From: E. L. Jones <jonee_at_meteoritecentral.com>
Date: Wed May 19 19:04:48 2004
Virtualy all the ferro-magnesium silicates (pyroxenes, amphiboles etc)
are by definition iron bearing. I don't think they are magneticlly
attractive. Magnetite, usually in very small grains, can occur in
them. Alteration by water can produce hematite which can be
magnetically attractive and usually is. I just observed a sample where
a film of hemitite was less than a half milimeter thick and it made my
magnetic wand jump to it as if it were iron plate.
>I'm sure the mineral magnetite is your source of paramagmatism. Igneous rocks are often magnetite rich.
>Iron would also be in many other minerals...but magnetite is likely your source of attracting a magnet(paramagnetism).
>I understand that mafic igneous rocks contain iron but does anyone know what
>form it's in and how it's distribution is characterized? Is this iron content
>high enough to make it magnetically attractive? I have a batch of interesting
>wrongs that I'm trying to sort out.
Received on Wed 19 May 2004 07:07:13 PM PDT