Hi David, Nigel, Debbie Michael, Thilo, Chris- Thanks for your replies!!!  
The 'artifacts' in question were brought to me by 'collectors' because they were erupting in disfiguring blisters or fur of bright blue and white corrosion.  Although they were all purchased for rather insignificant amounts of money as mementoes of travels or because they were 'cute'- I don't think the owners really thought they were ancient, BUT the curator, would never state the obvious.
A parallel' to one of the pieces, the ibis,was spotted in the window of a shop on Coptic street.  These pieces were dubious!!!!  Egypt is full of this kind of tourista.  And Nigel's point about NO cuprite is a good one.--there wasn't on any of them.  Not even that terrible crystalline cuprite that I have seen on some 'fakes'.

I was actually looking originally at just the corrosion.  Malcolm Back and Bob Ramik who are in Mineralogy, here at the ROM, do the XRD and XRF work.  We have also been working with Tom Chase.  What we wanted to see if we could do , was identify /categorize these very active disfiguring forms of corrosion, visually by colour or corrosion crystal shape.  Also, since it hardly looked like bronze disease, I wanted to know what I was 'stabilizing'.  In the past, I have found that chalconatronite does not respond to conventional treatments-BTA or control of Rh.  It just spews bright blue powder, continually.
So, with that in mind,  we tried to ID this corrosion.  The white efflorescence on the ibis matched the data for a zinc, sulphate chloride hydroxyl hydrate compound. XRF showed presence of major Na and significant Pb and Fe.  The blue corrosion had major Cu,Zn,Cl and sig. Z,Na, and Pb;also Ca, Fe and possibly S.  No mineral ID.   ((Published in Rotunda, Spring 1998.  There is a photo of the Ibis and the corrosion in question, if any of you have the magazine.  (I hope I didn't embarrass myself, with what I wrote))
I assumed at the time, that some of this stuff was from the patination process or perhaps, 'cleaning' solutions. Although the 'crust', would lead one to believe it had not been cleaned.
The strange corrosion products continue to tease us.  I do have bright blue and white corrosion on some of our museum stuff.  Some of it, unfortunately, is related to storage and treatment.

The pieces the public bring in though are even more problematic. Lately, there have been over seven.   The Museum in Montreal was considering a 'gift ' of a statuette of Isis with Horus, no provenance.  They sent photos and asked my opinion on the piece .  Comparing the pustules on the surface to those of the Ibis mentioned above, made me suspicious.  Also it had a rather uncleaned appearance.  It look like, excuse me, junk.  So my advice was  that everything is worth something, and it depended on the 'price' they had to pay.  From the photos, I was suspicious.  I did not feel it was a top' piece,even if I went and cleaned it mechanically .
The curators response, was that it was LATE(safe as always).  The corrosion was too much like the Ibis and other zinc bearing corrosion products which we have examined.  Not at all like 99% of the material in our collection or other collections I have seen.   Debbie mentioned the presence of Zinc from cleaning solutions-but these didn't look 'stripped'.  Just junkie.  Then why so much Zinc?? Cuz they are cheap fakes of brass?   
My question was how 'late' did  Egyptian style statuettes start using Zn as a component.  Late Roman? or even later.
Lucas in Egyptian Materials  doesn't even mention Zinc.  So I wanted to know, those of you, who examine provenance pieces, if recent work had shown something different.
I would love to have cut the pieces in question open and have a proper look.  But, the owners, probably wouldn't have wanted holes,  and I didn't want to fill them.  Who would pay?? In future , I will ask.
I still feel these were 'tourista', but I would like to sort out the Curator once and for all,  Not everything is LATE!!
David, if I can dig up the original samples or data, are you still interested???Thanks, Everyone for your input!!  This actually makes work fun. 
Susan

>>> "David Scott" <[log in to unmask]> 05/19/99 04:41PM >>>
we have found zinc-containing copper sulphates (essentially a zinc-substituted brochantite) called nauwamite, on clocks from the Wallace collection which are of interest in the zinc-containing salts ( of which there are quite a number) ....we could look at the XRD for you if you have a pinhead or smaller sample by powder diffraction Debye-Scherrer......


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