Dacitic is an adjective used to describe a type of volcanic rock with a high silica content and a composition between andesitic and rhyolitic rocks. Synonyms for dacitic include trachytic, porphyritic, and microcrystalline, among others. Trachytic refers to an igneous rock with a characteristic trachytic texture, formed by the presence of large phenocrysts in a fine-grained groundmass. Porphyritic describes a rock with large crystals, or phenocrysts, embedded in a finer-grained groundmass. Microcrystalline implies that the rock has a fine-grained texture, with crystals too small to be seen by the naked eye. Overall, the term dacitic is just one way to describe the unique characteristics of this specific type of volcanic rock.