Pyramidion

A pyramidion (plural pyramidia) is the uppermost piece or capstone of an Egyptian pyramid in archaeological parlance. They were called benbenet in the Ancient Egyptian language, which associated the pyramid as a whole with the sacred benben stone. In Egypt's Old Kingdom, pyramidions were generally made of diorite, granite, or fine limestone, which were then covered in gold or electrum; while during the Middle Kingdom and through to the end of the Pyramid building era, they were built from granite. A pyramidion was "covered in gold leaf to reflect the rays of the sun"; during Egypt's Middle Kingdom, they were often "inscribed with royal titles and religious symbols."