Hyaloclastite is an aggregate of fine, glassy debris formed by the sudden contact of hot, coherent magma and cold water or water-saturated sediment
Coquina is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically-sorted fragments of the shells of molluscs, trilobites, brachiopods, or other invertebrates
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock