Serpentines + Alabaster

Quoted text begins.I'm a geologist and I'd like to help you.
Daniel
End of quote.

Hello Daniel,

Serpentine (green) stone is found in this part of the
world down in Cornwall on the Lizard Penninsula - but
I understand that it's quite a hard stone to carve. The
only sample of this Serpentine that I have, has been
turned on a centre lathe and has a very high surface
finish. The other type of 'serpentine' that I have is
from north Cornwall and is deep blue/green in colour -
it's so soft that you can scrape the surface away with
a fingernail and it has a slightly soapy feeling when
the dust is rubbed in between the fingers. I have no idea
what the chemical composition of this stone, but would be
interested to find out.

There is someone here on a course at the moment who has
asked about how Alabaster is formed and what causes
different shades of colouration from red through yellow
to green? Plus - what period of geological time was
Aalabaster formed in? Was it during the Jurassic period?

Hope you can help on this one Daniel?

Paul Crabtree.

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