Dear ConsDist list members I have an inlaid blotting book composed of ivory, possibly jet, and some form of black material, as well as a small amount of coloured intaglio pieces (?), all adhered to a wooden backing. The black material looks a bit like niello, and is degrading badly (crystallizing, expanding, and crumbling away from the support). I tested it with our handheld XRF and it showed peaks for tin, but not for silver or sulphur, and only a tiny possible peak for copper and zinc, as well as iron (and maybe a hint of lead), which is probably just dirt. The only other peak of significance is likely calcium. When looking at the corrosion crumbs alone, the only peaks were tin, with a smaller peak for calcium. I did a quick scan with Dr. Google and our library of books, and couldn't find any reference to a niello/inlay substances composed of just tin. Regular niello might contain small amounts of tin, but I should be detecting Ag, Cu, and S with it, and I'm not. I also found reference to a mercury amalgam material (like what's in our teeth) that can spontaneously decay. It sounds like it might give the crumbling and disintegration that I'm seeing in the object, but I'm not detecting any mercury. Metallic tin might be used in inlay, but it is not black. The acquisition record for the object gives no indication of artist, origin, or materials. Visually the object looks similar to images of Visagapatam inlayed wooden objects from India, or perhaps a bit like Bidri niello, or inlay work from Iran, Turkey, or India, where coloured lac might have been used, but there is no mention of tin with this. Under the microscope the material and its degradation looks more mineral and crystalline than organic anyway. Does anyone have any experience with this type of material? Can you give me any information of composition or degradation of the materials? I can send images of the object and microscope images of the degradation if you are interested.
Thanks, Valerie Tomlinson Valerie Tomlinson | Conservator | Auckland War Memorial Museum | Tamaki Paenga Hira | The Domain, Private Bag 92018, Victoria Street West, Auckland 1142, New Zealand | www.aucklandmuseum.com | M | P +64 9 306 7070 ext7304 | F | E [email protected] Auckland Museum Trust Board ("Auckland Museum") accepts no liability for any opinion contained in this email. The material in this email is confidential to the recipient named above. If you are not the intended recipient: please do not copy, use or disclose this communication; please notify us immediately by email or by telephone (64 9 309 0443) and then delete this email. Where this is a communication unrelated to the business of Auckland Museum, Auckland Museum does not accept any responsibility for its contents. ##################################################################################### This e-mail message has been scanned for Viruses and Content and cleared by MailMarshal ##################################################################################### ****** Unsubscribe by sending a message to [email protected] Searchable archives: http://cool.conservation-us.org/byform/mailing-lists/cdl/
