Augen gneiss is a medium to coarse grained metamorphic rock composed of mainly quartz and feldspar with smaller amounts of mica. The especially large megaclasts of feldspar are called "augens" which is German for eyes. Gneiss is formed by high temperature and high pressure action on formations of igneous or sedimentary rocks. This specimen was collected from Easter Ross in the Scottish highlands.
These specimens of sandstone have no particular significance, and are included in my collection, simply because I collected them. I collected them from a newly opened layby in Enville, Shropshire. I was travelling from central Wales to the West Midlands. a frequently travelled route, and stopped for a five minute rest in a layby. I took the opportunity to explore the freshly excavated bank at the rear of the layby and found many sandstone nodules, etc. with varying composition. These are just a few, and my research tells me that this locality is recorded as being the Enville member, Sandstone in the Salop formation.
This specimen appears to be composed of compacted volcanic ash with inclusions of small volcanic bombs, or lapilli, This type of bomb is referred to as a " cow pie" bomb, and is the result of fluid magma falling from a moderate height and reaching ground level before solidifying. It was collected from Gilwern Hill quarry, Howie, near Llandrindod Wells. This area is part of the Builth inlier. and is characterised by volcanaclastic rocks of the lower to middle Ordovician period, probably resulting from nearby volcanic activity.
I have a very large basement area, and this photograph is my store of all things geological, including my collection of rocks, fossils, and minerals. There are many hundreds of mineral specimens, and it will take me a long time to put all of them on the website. Many minerals have been collected here in the Central Wales Orefield (CWO). Unfortunately many of the sites have been overgrown, or "landscaped", leaving only a handful of local sites which may still yield the odd specimen. The listed specimens can also be viewed in picture format by accessing the "Bagley collection" on the home page. I would appreciate feedback on any of my postings, and thanks for looking.
This specimen of cut and polished vein breccia is interesting for two reasons. The first point of interest is that the breccia/wall rock boundary is very prominent. Next, there are very angular shards of the same wall rock in the breccia, demonstrating the power of hydraulic action. The cream coloured mineral is a dolomitic carbonate, and there are areas of a bronze coloured mineral which is sphalerite. The inset picture shows the unpolished rear of the specimen, and it was collected from the Cwmrheidol mine, West wales, by John Philips in the 1960s-70s