Sillar

Sillar is a variety of rhyolite, which is a type of volcanic rock.

A pink variety of sillar owes its colour to crystals of hematite within the rock.

Sillar is found as pyroclastic flow deposits of tuff near volcanoes in southern Peru,[1] for example the now-extinct Chachani volcano which erupted flows of sillar during the Pleistocene epoch.

Sillar facies Orvieto-Bagnoregio Ignimbrite (black blocks of scoria in red tuff) occurs at Civita di Bagnoregio in the Vulsini volcanic district of central Italy.

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