Hi Rory,
Bernard's recollections are not dissimilar to mine and I agree with his
conclusions. I met a farmer, a Gloucestershire man, in S Central Wales a
few years ago who in his former career had worked at Yate and had a fair
few celestine geodes decorating his house, both inside & outside. I have
not been there myself but looking through his collection was struck by the
variety of colours - white through pink to a bluish tint. Chunky crystals 1-
2 inches in some cases. In 1983 running a car-boot near Evesham, selling a
few "rocks", I met a woman whose husband was a bulldozer driver & had been
working on a site in S Gloucestershire. I was invited to their house to
identify a "rock" which turned out to be a 3ft hollow boulder covered in
waterclear celestine xls to 3 inches. Did make them an offer but they kinda
liked it! Good for them I now think! Many large specimens must stil lurk in
rockeries around Gloucestershire & elsewhere. Amethyst - very unlikely.
These are evaporite deposits which means that we are dealing with
relatively soluble things. Celestine, strontianite, gypsum, baryte, calcite
etc all fall into the category of potential species here & elsewhere.
Quartz is extremely unusual in such cases. Blue celestine is a far more
likely candidate. It's a beautiful pale blue colour - a bit like West
Cumbrian fluorite but less intense - & well-crystallised but not as purple
as amethyst.
A similar mineral assemblage is present in the Keuper Marls in South Wales.
Not that surprising, it's near to Yate (in geological terms). After
rockfalls between Penarth and Lavernock, WSW of Cardiff, a few years ago,
some beautiful sapphire-blue crystals of celestine were collected. These
certainly surpassed those mentioned in 1858 by Greg & Lettsom, from Barry
Dock. Ian Jones was on the scene & recovered some very fine pieces. Today
you may get part-crystals but of good colour - but please watch the tides &
wear a hard hat AND keep your ears open for stuff coming down!
Regards - John
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