These thunderegg agates or Lithophysae are from the mountains in the far south of France – near Frejus, not that far from the French Riviera and Cannes. These are among the smallest (on average) thunderegg agates out there – and also incredibly beautiful. These stones are one of the most prized thunderegg agates there are and they are only getting rarer since the site where they are found has been closed (as so many of the best seem to be). I was lucky enough to find a quite large unpolished stock of these eggs, which has led to this being the largest single gallery on the Eibonvale Website. I hope that these will give some idea of the delicate and colourful beauty of these eggs. These are not mighty display pieces, but tiny little miniatures with the beauty in the fine detail.
The marriage of matrix and agate takes on a whole new meaning here, creating a melded whole that you can just dive into, finding continually smaller and smaller detail. And the smaller you look, the more the magic stands out. It is the intense and refined complexity of these eggs that really make them. The agate is usually very finely banded and the stones frequently contain levelling lines and crystal of various types. They are also prone to ‘onion ring’ formations, which, in thundereggs as a whole, is extremely rare. This means that the agate is sometimes very convoluted and deeply married to the matrix, creating a melded whole that you can just dive into, finding continually smaller and smaller detail. Esterels are also highly prone to cracks and to weathered holes, maybe where certain crystals have dissolved away.
Cracks are a fact of life for the Esterels though. If you don't get on with cracks, then you will find this a very frustrating species of Thunderegg. And the cracks can be brutal – simply because of the delicacy of the agate they cut through. Cracks are cracks though, say I. They are a part of the thunderegg's 'life' and personally, I dont mind them much. Another curious feature of these eggs is their tendency to 'decayed holes' which appear to be caused by the weathering away of certain specific types of crystal, still present in a few specimens.
Esterel Thundereggs are surprisingly difficult to photograph accurately. There must be some quirk about them that confuses digital imaging devices. In this case I have used a scanner to match the image as closely as possible to the original stone. Some minor colour variation is possible though!
This gallery contains some really fine classic specimens, and also some more unusual, uncharacteristic and bizarre specimens.
Finally, the Esterel thundereggs can do some interesting things under ultraviolet light. The florescence is very dim - at least under my not very powerful lamp - but can be very colourful with different patches of the egg showing different colours. It was very hard indeed but I did manage to capture an image of one of these. It required a bit of processing to tidy it up thanks to my not very high quality camera - but here it is: