PICO DEL MARTILLO The hammers for geological exploration usually have one side with a flat head and the other with a beak to investigate the hardness of the rocks. Some hammers have a single beak, others are double beaked. They're geologist's peak hammers. There is still another type called duck beak by the flattened and elongated beak. Some synonyms, words or similar expressions may be geologist's peak hammer, duck pickt hammer, double beak hammer, flat-billed hammer