I found another interesting rock on the local beach in Dorset - it looks like labradorite when it is wet but not sure if it is? If anyone could id it for me please, many thanks.
Yes - I think you're right.
The colour and the cleavage are right, as is the general coarsely crystalline structure of the specimen.
Off-hand, I can't think why you'd find labradorite on a beach in Dorset naturally.
But exotic stones occur on many a beach due to man's activities.
Thankyou for the id! I've no idea how to polish it without breaking it - I was thinking of using a tumbler but I'm afraid of cracking it. So far I've just used toothpaste and a brush which seems to be working as it's beginning to show some colour without having to wet it. May take me some time though!
Strangely there seem to have been quite a few unusual rocks on the beach lately, not sure why!? I suppose the sea could carry rocks/crystals from anywhere or do they only travel a certain distance? or maybe someone dropped it or it got washed off a boat!? It certainly is a mystery. Still yet to find diamonds or rubies though - will have another look tomorrow!
Labradorite apparently is found in Cornwall( I remember my schooldays re Kaoline ,China clay pits rich in Feldspar), The Lizard, how far is that along the coast to your nice find
I think it's an Alien!
Try explaining that to a family of four in the middle of the Holderness coast who want you to id this fantastic rock they had just found.
We see many rocks like this from Scotland and Scandinavia use for sea defences on a very large scale.
As you said - due to man's activities.
On which beach did you make your find, for some bizzare reason I assumed it was the South coast, because its just 112 miles from the the most easterly point of the Devon coast to the Lizard. I imagine over time your find was caused by tidal drift
Took the grandson collecting on the Holderness coast this morning at Tunstall (Sand le Mere caravan park) and we came across two specimens very much like yours.
You find these more or less all over the Holderness.
The larger boulders weigh several tones and have multiple drill marks along there sides but because of the energy on the beach they get broken into smaller boulders.
Wow your grandson must love collecting them! - you're lucky to have so many near you! Where we are it is mainly just flint and sandstone on the beaches.
Have you tried tumbling them? I've been sandpapering mine and it's getting more sparkly but I'm just scared it will all crack if I tumble it!?
The grandson loves fossiling (he is 4 and a half) and often spots things that i miss, he is a good companion and very entertaining to be with.
We don't usually collect minerals like this because they are imported on to the Holderness coast to be used as sea defences, they come on barges from abroad by thousands of tonnes.
The Holderness is a high energy beach system and it soon starts the natural proccess of wearing them down.
Just a quick thought though - are you hand sanding your specimen? this will take a long time, why not use a bench grinder/sander or a sandpaper barrel attachment that fits on to a Dremmel.
I will post an image of the barrel attachments if you need one.
It's great that your grandson enjoys fossil hunting with you - I remember my brother and I loved finding interesting fossils, rocks and crystals when we were younger and were always digging great holes in the garden (unfortunately we didn't live near the coast then but our house was next to where the Marconi factory used to be so we were always finding huge lumps of quartz crystal.)
I'm really surprised they use labradorite as a sea defence as I always thought it was only used for jewellery etc. Thinking about it we also have sea defences - I haven't really taken much notice of the rocks used as I thought it was just granite and it's all in wire caging. Some of the caging was ripped apart during the storms earlier in the year so it's very likely that that's where it came from. I'll have a closer look next time I'm down there.
Yes I have been hand sanding it and it's taking forever! An image of the barrel attachment would be great thankyou!
If you are hand sanding then do-it under a running tap, the water lubricates and helps the proccess.
Please have a look at the images I have attached, the sanding barrels are easy to spot but the other two are diamond coated burrs (not realy expensive) used to also remove matrix.
One has a 3mm shaft with a 8mm ball head and the other has a 3mm shaft and a 6mm tear drop head.
Don't forget to use safety glasses because when things go wrong with a rotary tool they go wrong FAST!
That's great thanks Tabfish. I've now sanded it as much as possible (it seems very brittle - maybe because of the salt from the sea) so I have just smoothed it as much as possible and then varnished it. I have also since found another piece and have done the same to that one. The second piece is a lot flatter so was a lot easier to work with. I will add some photos later of both pieces.