In a message dated 6/10/2010 10:35:46 P.M. Eastern Daylight Time,
[log in to unmask] writes:
Very
interesting Steve. I “thought” petrography would be useful but my problem is
that we don’t want to remove any stone and there is no damaged area either.
Eric:
Make it hard, will you? And this is an exterior facade exposed to the
rain which might have already washed off any fire soot, or it could be
contaminated with diesel soot from city traffic.
The surface could be sampled with tape, which would then be examined.
This wouldn't be as accurate as examining a chip sample of the stone, but might
be adequate. The issues are that not all of the soot will be transferred to
the tape, and that the soot will be on the sticky side of the tape under the
particles of dust, etc. that transfer to the tape.
On the other hand, some soot is fluorescent, particularly if something oily
or resinous was burning. Maybe we should just go up to the facade at night
with my high-power blacklight and look for streak patterns above the window
vent areas.
Steve Stokowski
Stone Products Consultants
508-259-3536 (cell)