The explosive eruption of the Thera volcano circa 1470 B.C. directly destroyed the Greek settlement at Santorini that had been established on the volcanic island. This is a likely origin for the Atlantis myths. So much ash fell on Crete that the island's agriculture failed, dealing a crippling blow to the Minoan culture. Typically made of material ejected vertically from the vent that then collects around the vent. The scoria used in landscaping and in commercial barbecues is typically excavated from the sides of cinder cones.
Some volcanic gasses are highly toxic.
While glass, in the strict sense, is not composed of crystals, there are commonly small crystals in most natural glasses. Pyroclastic breccias are composed of angular lapilli or blocks generally in a matrix of ash or dust. If the rock's volume contains less rock material than vesicles, it is said to be a scoriaceous rock or a scoria .