Folks,

Best I can tell the crystals are silver nitrate. I don’t even like to think what conditions caused this crystallization, but it could be that the pins were made with a combination of silver and copper, which when exposed to moisture over long periods slowly crystalized the silver.

 

Lynn

-------- Forwarded Message --------
Subject:        [Nhcoll-l] Attention conservators: Insect pin corrosion
Date:   Mon, 20 Jul 2015 18:05:25 +0000
From:   David Notton <[log in to unmask]><mailto:[log in to unmask]>
To:     NHCOLL-L Listserve ([log in to unmask]<mailto:[log in to unmask]>) <[log in to unmask]><mailto:[log in to unmask]>


Nat. Hist. Conservators (others may look away now)

I'€™ll be grateful for an opinion on the metal corrosion shown in the attached image, it depicts dark coloured dendritic growths, altogether different from the regular green waxy verdigris. Any ideas what is its composition/formation/what kinds of pins are prone to it/prevention?

Many thanks!

David

David G. Notton, Senior Curator (Hymenoptera)
Department of Life Sciences, Insects Division, Darwin Centre - room 315, The Natural History Museum<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.nhm.ac.uk_&d=AwMGaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=vu1SgbfmdUDN1UWNLztMThibU3NPdXlRw3tT1MoYIUU&s=xwtnsXnSDsvmPzMh3F9Gin7gtXa2-bHl5i1lYW5e8d0&e=>, Cromwell Road, London, SW7 5BD, United Kingdom. 0207 942 5974.

My publications: David Notton Researchgate profile<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.researchgate.net_profile_David-5FNotton&d=AwMGaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=vu1SgbfmdUDN1UWNLztMThibU3NPdXlRw3tT1MoYIUU&s=7xyw0ITUN0HdP-KOwfH1MiEjGTRfI8EFr8By6Uy5vYg&e=>
Museum data: Natural History Museum Data Portal<https://urldefense.proofpoint.com/v2/url?u=http-3A__data.nhm.ac.uk_&d=AwMGaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=vu1SgbfmdUDN1UWNLztMThibU3NPdXlRw3tT1MoYIUU&s=EmJ2eBf59GeiEY-LSWCrVg51v-KBE19qiL6eGDWFRCo&e=>







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