Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin
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
From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock