Porcellanite
Porcellanite worked into Neolithic axes, Northern Ireland
Porcellanite or porcelanite, is a hard, dense rock somewhat similar in appearance to unglazed porcelain. It is often an impure variety of chert containing clay and calcareous matter.[1]
At Tievebulliagh, Northern Ireland porcellanite is a tough contact metamorphosed hornfels formed from a lateritic soil horizon within a basaltic intrusive/extrusive sequence. It is the site of a Neolithic axe or stone tool quarry.[2]
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