Today’s mystery object has been selected by a very helpful work experience volunteer who was assisting me in the collections yesterday, so my thanks to Harrison! He is rather more cruel than me, so there’s no multiple choice on this – we just want you to see if you can work out what it is. I will attempt to answer any questions (time permitting) since our broadband seems to have been sorted out at home.
So here it is:
Here are some more detailed images that might help:
Make your suggestions in the comments section below and I will provide the answer on Monday – best of luck (I have a feeling you may need it)!
Zygoma 
As promised to Paolo the other night, here’s my answer for when I’m stuck:
It’s a scale bar, with some object next to it for comparison.
More seriously, I’m going to guess that it’s a slice through a large fungus of some kind.
Not a fungus I’m afraid!
Given my abysmal failure last week, I’m feeling a bit more cautious this week.
I originally thought some sort of tusk or horn, but most of those appear to have a more distinct “core” – this just seems to have some discolouration in the centre (no real structure). It doesn’t seem to have any sort of annular banding, which you seem to see in horns and tusks.
The surface cracking and warping suggests to me that it was something that started off with a higher moisture content than it currently has but not a much higher water content (such as a fungus would have).
Can’t help thinking the reddish markings in the middle are telling me something.
You’re correct in saying that it isn’t a fungus. The warping and cracking is due to humidity differences, but as you say, there’s not enough to suggest something that you would think of as wet or even particularly moist. The object has been in a museum since 1912, so a bit of distortion should be expected!
The markings in the middle are informative, but the overall structural composition is pretty key.
I’m trying to work out whether the scoring I can see in the top image is part of the structure, tool marks from the initial cutting or marks from a subsequent cleaning. I think it’s one (or both) or the later.
I think those marks are from the original cutting
I thought it was a dried melon or some kind of vegetable but the 2nd pic (close up of rim) look like a piece of wood.
Do funghi have fibres like that? Wood, certain types of veg (like poor man’s shark fin), and meat are the only things that spring to mind.
Are those seeds in the middle of it?
Fungi are fibrous, but it’s not a fungus. There are no seeds in the middle, those are more fibres in cross section… the fibres are a good observation!
Is it antler or horn?
Antler or horn that thick?
Maybe collected from a freakish specimen, a tiny dikdik with a massive horn? 😉
Fibres down middle could either mean hair (with some sort of accretion around it) or something vegetable (but fairly low water content) which rules out fruits and I don’t think nuts have any internal structure. I wondered briefly about amber but I don’t think it’s that. If it were the stem of something I’d expect it to be fibrous all the way through.
My first instinct was that it looked like a elephnat tusk in cross section, but the centre discolouration doesn’t look quite right. However, the flakey texture in the second picture makes me think it looks at least partly mineralised.
Is it a cross section of a mammoth tusk?
Not mammoth tusk and not particularly mineralised (although maybe a tiny bit) certainly not fossilised though!