Golspie beach is in a sad state. Not only has it lost much of the sand that used to be so good to 'stretch our legs' on but also the flotsam left along its tidelines lacks anything of interest. Even the birds have left - on our last walk all we saw was one flight of a dozen or so oystercatchers, and some gulls and crows. So, to give myself something to do I've turned back to an old friend....
....geology. It's my degree subject but has suffered badly in recent years in competition with the local wildlife and the archaeology/history. There is some very good geology locally, but I simply don't feel motivated, and it's a sign of desperation when, walking along the exposed bones of what was a good beach, I show interest in the large, imported rocks that form the breakwater. These include ones, like the one at bottom left, which have...
....some large minerals in them. I used to be an avid collector of minerals, being prepared at times to buy some which I had little chance of finding myself, but my collection has been given away and I now only have passing interest.
I think this lump of rock - it must weigh a tonne - is a pegmatite, formed by scalding, high-pressure, element-rich waters moving up from deep underground to be injected, in this case, into metamorphic rocks where the elements crystallise in large veins to form minerals - quartz, felspars, micas and iron-magnesium 'mafic' minerals.
Not far from this rock was another, more simple pegmatite rock, formed, as far as I could see, of pink felspar, possibly orthoclase, and and a white mineral which might also be felspar or, possibly, quartz.
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