There has been some discussion on social media recently about "rock wedges" -- following the article by Mike Parker Pearson and colleagues about the so-called "wedges" found in rock fractures at Craig Rhosyfelin.
Reconstructing extraction techniques at Stonehenge’s bluestone megalith quarries in the Preseli hills of west Wales,
Mike Parker Pearson, Richard Bevins, Nick Pearce, Rob Ixer, Josh Pollard, Colin Richards, Kate Welham
Journal of Archaeological Science: Reports, Volume 46, 2022, 103697
So if anybody wants to convince me that a lump of rock found in a crack or fissure anywhere in Pembrokeshire, either in bedrock or in broken rock debris, involves human beings using bits of stone as "rock splitting" implements, they need to come up with some pretty powerful evidence. The evidence I have seen thus far, in support of such claims, is very thin indeed.