Folksy Ltd

Rocks and fossils

(atalantaninetofive) #1

Sam, (mermaids purse) made a post about fossils,Sasha Garrett contributed by saying we could start a thread,the more I thought about it the better it got and perhaps we could have a swap shop.e.g,some things may be common and local to us but scarce in other parts of the country so we could swap or just help each other out with found items,post what you are looking for.
But the main theme would be for those of us that want to talk rocks and fossils (unless I run off thread onto the life of Bwian or something).I may find myself out gunned by Sam and Sasha,they seem to know a lot but I would still chip in with my 10%.

(Sasha Garrett) #2

I’m going to say you know far more about fossils than I do but I like rocks the more unusual the better. Here is the marston marble from Marston Magna in Somerset (which I got at a rock show in Surrey having not been back to the west country in a number of years), someone found a small deposit of it in/on a hill and has been looking for more ever since.

Not a brilliant photo but you can see the creamy ammolite shells in a bitter chocolate brown ground with viens of quartz. These will eventually end up as pendants - I need to practice making little shell shapes first.

(atalantaninetofive) #3

I have never seen marble that nice,I take it you will practice on something more readilly available before moving onto the marble.I asked the local stone mason about offcuts to make ring boxes with but it seems it all goes for chipping now or that was his excuse.Probably worried I was going to make mini monuments for Newts.

(Samantha Stanley) #4

Dammit @SashaGarrett! I have to get hold of some of that stuff-much better than fossil jasper. The shells look almost as if they have been drawn on :grinning:

Sam x

(Sasha Garrett) #5

His name is Mark Varah, based in Stroud but has a year round stall in Bath near the assembly rooms/ abbey (or so he told me, I haven’t yet sent my parents to check it out). He had other fossil materials on his stall at the rock/ bead show and plenty of cabs cut from UK sourced rocks. Bath is a lovely place for a weekend away…
I’m not sure if it is a true marble or if that bit of the name has been applied for marketing purposes but it has a wonderful polish and the quality of is cutting is excellent so they will set like a dream when I get round to it (I have to make some more fordite cufflinks first, then a fossil coral pendant commission).

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(Samantha Stanley) #6

I don’t think it is marble because then the shells would not be present. Marble is generally formed from limestone (which could contain the shells) but then it is subjected to intense pressure and heat which changes the rock into marble and would destroy the fossils. It is probably Jurassic limestone (Somerset is on that strata) and that would account for the high numbers of ammonite fossils. The quartz veins are most likely the remains of sea sponges which have accumulated silicon particles through their lives and then fossilized when that layer was buried perhaps 150 million years ago.

Some paleontologists think that the large numbers of ammonites in this strata are as a result of the creature’s breeding cycle which may have been similar to that of the cuttlefish today. Large numbers of the sea snail would have congregated together to breed each year and then died as soon as they had laid their eggs, leaving the sea floor covered with a thick layer of shells. It is possible to observe the results of the cuttlefish breeding cycle right now if you are on the South Coast and near a pebbly beach with a few groynes (they like to glue their eggs to these). In the next month or so lots of cuttle-bones will start to appear on these kinds of beaches.

Sam x

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(atalantaninetofive) #7

A concur with you Sam now you have mentioned it,given how marble is formed.
There are beds around Essex that would have been full of fossil shells but they interact with acid,I think from Pyrite I need to look it up again to be sure.Anyway the result of the reaction is Selenite,sometimes the chrystals grow up to around 4" where I am.

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(Sasha Garrett) #8

Pyrite and water would give sulphuric acid (and a ferrous species) which could react with the calcium carbonate in the shells to give calcium sulphate which could crystalise into selenite. I’ve got a cab of that (well satin spar) in the stash just not sure how robust it would be for jewellery. I’m now feeling that I should spend longer in some of the other bits of the Natural History Museum rather than just skipping through the samples in the mineral gallery (I want the slab of malachite) so that I can drool over the contents of the Vault before heading off to the Wildlife Photographer of the Year exhibition. I’ve never really bothered with the dinosaurs bones or stuffed animals.

(atalantaninetofive) #9

I need to go and see if I can find some selenite,I have a use for it,as you say soft for jewellery but I have an ornament in mind and it should be o.k for that.

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(Jan Ryan) #10

This is one of my favorite rings I bought a few years ago, I took this photo of it laying on a pile of Lapis Lazuli that I’ve had for a while. The photo was taken a few years ago for my blog.

(atalantaninetofive) #11

Nice ring,nice lapis,nice shop. My bestus buddy is a big 7k ginger so I had to lay a fav on that one.

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(atalantaninetofive) #12

Thanks for the fb like Jan,I want like yours but it wont let me,try again later.

(Jacqueline Ostrowka) #13

Like the thread, makes interesting reading, :slight_smile: more into the minerals than fossils but that’s through not finding many fossils :slight_smile: I do love scouring the beach though specially East Yorkshire coast and that way on.
Lovely ring Jan @HandcraftedbyPicto and Lapis too, I’ve a lovely slice waiting for me to work on it (when i get around to it)

(Sasha Garrett) #14

You can find some interesting rocks on beaches - admittedly I picked these up on beaches in New Zealand but I’ll scour any beach in hope.

On the left is garnet in granite (garnet gneiss to be accurate but the buying public don’t always understand that, granite they know), on the right is the bowenite type of Pounamu (not to be confused with the jade forms of Pounamu) has a lovely deep green colour and translucency but the beach rocks are almost black with just a hint of colour where you get surface cracks.

(Samantha Stanley) #15

If you have a weekend free to go away over the summer I can suggest the Isle of Wight for fossils. Also Charmouth and Lyme Regis. These places give you the best chance in the country statistically to find a fossil, although nothing is guaranteed of course. Fossils ammonites turn up regularly on Portland too but many of them are far too large to carry away.

Sam x

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(Samantha Stanley) #16

I’ve had a dinosaur obsession since I was three and it extends to extinct animals in general. I’m actually quite jealous of @atalantaninetofive being able to find fossil sharks teeth on the beach. These are really cool fossils and there is an outside chance of finding a tooth from Megalodon, possibly the largest shark ever, which dates from around the Miocene period. The sheer range of life that has existed since the planet Earth was able to support it is enormous and much of it is incredibly weird! What is more, since only a tiny proportion of the animals that have ever lived have been fossilized, there may have been other kinds of animal that can only be guessed at…

Sam x

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(atalantaninetofive) #17

We steal some of the Yorkshire coast stuff here in Essex,it is brought down by the longshore drift,thanks for the Jet.

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(atalantaninetofive) #18

Of course anything can turn up in the U.K, in the days of sailing ships if they didn’t have a return cargo they would shovel ballast into the hold to stabilise the ship,on their return home they would shovel it out onto the beach so anything could turn up.Don’t think I would know a rough Diamond though if I saw one at my feet.

(atalantaninetofive) #19

I don’t know when I will go out again Sam,but when I do I shall keep you in mind.
But as regards jewellery, e-bay is swamped with wire wrapped sharks teeth,there has to be a better way to suspend them as pendants,I was thinking maybe pierce out a little plate with claws to go behind them, silver solder would zap them but if copper is used maybe soft solder.

(atalantaninetofive) #20

Nice photo too and do you use the lapis for carving or cabs? And did you take the photo?