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Hi Elizabeth - it seems you may have bone stained by vivianite. This is an iron phosphate material - I've occasionally seen it encrusting, or as a stain, or 'whiskers', on ancient and even relatively "recent" fossils and bone. It seems to form in anaerobic iron rich conditions on organic materials - bone, shell, etc. I'm not at my office/library so can't send any references right now - but Google, e.g. http://en.wikipedia.org/wiki/Vivianite http://www.galleries.com/Vivianite http://www.britannica.com/EBchecked/topic/631431/vivianite (see fun cross reference to 'odontolite' or 'bone turquoise' http://www.britannica.com/EBchecked/topic/425244/odontolite) for starters?. You mentioned that no metallic artifacts are in association - copper or iron? C'mon back later - and would love to hear from you and any others on this occurence. It's a fun mineral? Hydrated and often soft and fragile. It's also similar to another iron mineral that forms in anaerobic conditions - forgot the chemical signature. If you leave bones or teeth too long in anaerobic maceration prep water, teeth, especially, will often be coated with an amazing black-chrome deposit that looks like metal fillings!. I know from experience (!?) Best, Susanne Susanne Miller Faunal Analysis and CRM Services 1450 Antares Dr. Idaho Falls, ID 83402 [log in to unmask] ----- Original Message ----- From: Moore, Elizabeth (VMNH) To: [log in to unmask] Sent: Tuesday, July 17, 2012 3:09 PM Subject: [ZOOARCH] stained bone question I have a cow carpal that has been stained bright turquoise (blue green) in color. It does not look like any copper staining I have seen before - it's too blue. It is from an inn/hotel built in the 1850s in south central Pennsylvania (eastern United States). Has anybody ever seen any bright turquoise staining? I don't know what color other metals stain except for copper which is usually more green than this. No hints present from the other artifacts in this context. Elizabeth _________________________________________________________________________________________________________ Dr. Elizabeth Moore Curator of Archaeology Virginia Museum of Natural History Martinsville, VA 24112 [log in to unmask] 276 634-4176 www.vmnh.net