Bassett and Grylls exotic semiconductor field trip

The second search for exotic semiconductors was at Bassett and Grylls mine in Wendron. This is a very different location to the Porthtowan trip as it was a tin, rather than copper mine. It is well overgrown but still with quite of a lot of visible infrastructure from ore processing activities that went on here.

This location was initiated by a discovery that hematite I'd found from here previously seemed to have a low resistance in contrast to hematite from elsewhere, so I wanted to see if I could find some more usable quantities for sound making. It's also a site rich in pale brown cassiterite. I also wanted to see if there was any magnetite present here, as I'd noticed magnetic material in the stream previously when searching previously for alluvial cassiterite.

The rocks collected, the black veins consist of tourmaline - which often hosts more minerals. The red rock on the left side in the middle is a piece of slag with a big bubble in and a patch green copper secondary minerals visible.

Any remaining waste piles here have either been flattened or are completely overgrown. Due to this and the infrastructure present I only look at loose rocks on the bare surface and on the paths across the site. There is a lot of industrial process waste (slag) in the ground here, a lot of coal dust too - which coats everything and makes it look like there are crystals everywhere.

Using a magnet I found an extremely magnetic, seemingly crystalline dark rock - which I was pretty happy about as it resembled magnetite. Later on testing it it even provided weak but detectable semiconducting properties with extremely small pyramidal crystals on an exposed area. However when I tried to split it to expose more, I discovered a malleable metallic substance - which means it's probably a by-product of the smelting waste found here. It's quite possible that the crystals are in fact magnetite, just artificially created - but that is outside of the scope of this project (we are only interested in 370 million year old semiconductors).