I'm with sanmateo...Not a rock, but many rock shops do sell samples of all sizes and colors of glass slag, labeled also as slag glass. They cool looking.
99 percent sure its glass, nice lead content I bet as well with those colors. If you could tell us where it was found down to the town i bet we can figure out what factory/ shop it came from.
looks like two separate items
Having said that, they look awesome, perhaps worth something to someone, maybe marble collectors?
need to know the size
near a marble factory?
Thanks all for you help, all i know is that it was dug in Cardiff. I was passing a crystal shop yesterday and showed to a women in there and she was unsure what it is and said it might be made of resin and man made but she still looked baffled by it. Size is 10x8x6cm