I found a cluster of what look like dark and light blue coloured crystals on a Dorset beach this morning. Or it could be small pieces of glass stuck together for some reason!? My brother also found a few of small pieces in a similar area of the beach a couple of weeks ago. Could someone please id it for me please as I have no idea what it is! I have added some photos with a 20p in the first on so you can see how big it is. Many thanks!
I guess there's a hint of copper minerals about the specimen - the colours being reminiscent of malachite and azurite. But to find such a composite on a Dorset beach seems very unlikely. And also, it doesn't look right for a natural aggregate of minerals.
I think it is a lump of man-made recycled glass or glass waste/slag.
Quite what would have been made with such a composition, I don't know.
(There are tests I could ask you to do, but many of them would be ambiguous in their results. The best test would be to thin-section it and look at it under transmitted cross-polarized light under a microscope. The isotropic and amorphous nature of the glass would be apparent, if that is what it is. Such analysis would be too difficult for you to do, methinks.)
If there is a local museum, I suggest you take it there to get an opinion (and let us know wht they say!)
Many thanks Mike - I will try taking it along to a museum. I think you are probably right and it is some sort of slag but it is strange that it's mainly blue in colour - no green pieces etc. Bits crumble off quite easily and it does seem to be made up of small pieces stuck together somehow rather than a more solid crystal structure.