| http://www.w3.org/ns/prov#value | - Mindat states that it is a mixture of cryptocrystalline grains of silica minerals held in a glass-like suspension ??? in other words, a super-cooled liquid, formed near the end of a volcanic eruption, when water and most of the other elements have already been ejected, leaving mainly silica, which then cools too quickly to crystallise.
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