<P> A pyramidion (plural pyramidia) is the uppermost piece or capstone of an Egyptian pyramid or obelisk, in archaeological parlance . They were called benbenet in the Ancient Egyptian language, which associated the pyramid as a whole with the sacred benben stone . During Egypt's Old Kingdom, pyramidia were generally made of diorite, granite, or fine limestone, which were then covered in gold or electrum; during the Middle Kingdom and through 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 ." </P> <P> Very few pyramidia have survived into modern times . Most of those that have are made of polished black granite, inscribed with the name of the pyramid's owner . Four pyramidia--the world's largest collection--are housed in the main hall of the Egyptian Museum in Cairo . Among them are the pyramidia from the so - called Black Pyramid of Amenemhat III at Dahshur and of the Pyramid of Khendjer at Saqqara . </P>

What is the top of a pyramid called