Complex sentence: The Hijaz mountain area includes the "Cradle of Gold" (Mahd adh Dhahab) in the region between Mecca to Madina, the only known Arabian source for workable quantities of gold.
Split into simpler sentences: The Hijaz Mountains include the "Cradle of Gold (" Mahd adh Dhahab ")" district, in the region between Mecca and Madina. It is the only known Arabian source for workable quantities of gold.