[net.sci] An opalescent puzzle.

cooper@pbsvax.DEC (Topher Cooper DTN-225-5819) (04/17/86)

The following was part of a posting in a local bulletin board.

    I frequntly wear opals, and have some that are brilliantly coloured
    and beautiful.  [My grandmother] told me she could not wear opals, and
    proved it.  She took my blue Australian opal triplet (opal covered in
    [quartz] crystal and backed with black onyx - protects a soft stone and
    deepens the colour) and held it in her hand.  It turned milky white and
    lost all colour.  I took it back and the colour returned.

Does anyone have any explanations for this phenomenon?

People may post their responses, or mail them to me.  I will summarize any
of the latter.

		Topher Cooper

USENET: ...{allegra,decvax,ihnp4,ucbvax}!decwrl!dec-rhea!dec-pbsvax!cooper
ARPA/CSNET: cooper%pbsvax.DEC@decwrl

jeff@rtech.UUCP (04/20/86)

>
>     [My grandmother] told me she could not wear opals, and
>     proved it.  She took my blue Australian opal triplet (opal covered in
>     [quartz] crystal and backed with black onyx - protects a soft stone and
>     deepens the colour) and held it in her hand.  It turned milky white and
>     lost all colour.  I took it back and the colour returned.
> 
> Does anyone have any explanations for this phenomenon?
> 
> 		Topher Cooper

Opals will absorb moisture from the skin.  When this happens, then turn milky.
When the moisture evaporates, they turn back to their original colors.
-- 
Jeff Lichtman at rtech (Relational Technology, Inc.)
"Saints should always be judged guilty until they are proved innocent..."

{amdahl, sun}!rtech!jeff
{ucbvax, decvax}!mtxinu!rtech!jeff