The valley in which Petra resides is known as the "Wadi Musa", meaning "valley of Moses", and at the entrance to the Siq is the Ain Musa, meaning "spring of Moses"; the 13th century Arab chronicler Numari stated that Ain Musa was the location where Moses had brought water from the ground, by striking it with his rod. The Jebel al-Madhbah was evidently considered particularly sacred, as the well known ritual building known as "The Treasury" is carved into its base, the mountain top is covered with a number of different altars, and over 8 metres of the original peak were carved away to leave a flat surface with two 8 metre tall obelisks sticking out of it; these obelisks, which frame the end of the path leading up to them, and are now only 6 metres tall, have led to the mountain being colloquially known as "Zibb 'Atuf", meaning "penis of love" in Arabic. Archaeological artifacts discovered at the top of the mountain indicate that it was once covered by polished shiny blue slate, fitting with the biblical description of "paved work of sapphire stone"; biblical references to "sapphire" are considered by scholars to be unlikely to refer to the stone called "sapphire" in modern times, as "sapphire" had a different meaning, and wasn't even mined, before the Roman era. Unfortunately, the removal of the original peak has destroyed most other archaeological remains from the late Bronze Age (the standard dating of the Exodus) that might previously have been present.