Fossil Or Natural Ore?

[Archaeolinz]

Hello, I'm totally new to the forum and in need of a little expert help from you if possible.

Last year I was undertaking a small archaeological excavation in a back garden and we were lucky enough to come down upon 6th century Anglo-Saxon burial remains. Amongst some glass and amber beads, decorated pottery and other typical grave goods we found these few objects (the last two are actually the same one back and front and I think is different to the other two.

I must really apologise that I didn't take the photographs myself and they do not have a cross section angle but they are circular with no obvious features internally such as radiating lines.

The area where we were digging is on the northern edge of the Berkshire Downs, a chalk ridge in southern Britain, with very little topsoil (average 350mm) over solid chalk.

My question is, are these fossils (which do crop up in graves as amulets) or naturally occurring nodules.

Any insights would be very gratefully received as I have been tasked with writing the report!

Thank you.

[Oxytropidoceras]

They look like former pyrite nodules that have been replaced by iron oxides as the result of weathering. The two nodules on the left might have been trace fossils, borrows, that had been pyritized and later replaced by iron oxides.

Yours,

Paul H.

[howard_l]

I don't think they are fossils, they look metallic, are they heavy? If they were in with 6th century remains I am guessing that (if they are iron), that they may be iron material placed in there for the occupants to use in the after life, and forge for tools or weapons. If not and natural occurring as geologic remanents in the soil they should be found outside of the influence of the 6th century artifacts.

[TqB]

The far right photo with its radiating structure looks like a typical marcasite nodule from the Chalk.

[Archaeolinz]

Thank you Oxytropidoceras and howard_l. I have just done a quick search for pyrite nodules and found something very similar in a museum in Wiltshire, UK (not that far away) see http://www.wiltshiremuseum.org.uk/galleries/index.php?Action=4&obID=154 . I'd been looking for ages before that but it's much more productive when you put in the right words!!

They are not particularly heavy but certainly look quite rusty. Fascinating that they were known as thunder- bolts. Unfortunately as they are naturally occurring in chalk I do not know whether they were specially deposited as funerary goods or an artefact of digging the grave and backfilling.

Thank you again for setting me on the right path.

[Archaeolinz]

Thanks TqB, I see what you mean. I've got lots to learn!

[howard_l]

They really do look like pyrite or marcasite, both have the same chemical formula but different crystal forms. Marcasite tends to be less stable as I learn as a kid, I placed some on a drawer while in high school. after a few years in college, when I came home I found a pile of dust.

I have never heard of pyrite being used to smelter Iron ore, just hematite, siderite or Magnetite. I am guessing the high sulfur would interfere.

[howard_l]

To be sure it is pyrite, grind some the residue is black and stains everything and there is a strong sulfur smell.

[Archaeolinz]

Thank you, I have not got the finds with me here but when I get access to them again I will try your suggested tip to test that they are pyrite.

If we today find these natural objects interesting and intriguing then I'm pretty sure the local inhabitants of the AD500's would do so as well and maybe even bestow them with 'supernatural properties' to accompany their dearly departed in their final journey.

[howard_l]

An easy test is the streak test if you can get a bathroom tile, use the back, Hematite streak would be reddish brown, Magnetite is dark brown and pyrite is yellowish gray.