many of those winding roads are ruled by gorilla figuerrilla fi. >> it will be too dangerous.er these beautiful, beautiful lands. it's a green fire obsession. >> reporter: he spent a lifetime chasing that obsession. an he's within of colombia's top gem hunters. >> it's an incredible feeling. it's very rare. >> reporter: for 40 year, he's tracked down the wofrld's most expensive emeralds. >> why is there so much security here? double locks on all the doors? >> it's worth a lot of money. >> reporter: they'll play top dollar for private collectors and big museums. he's so well known in bogota's emerald districts, sellers swarm us, hoping to catch his eye. >> $500 for all of them. >> reporter: is that a good deal? >> no, not at all. >> reporter: it takes a special stone and that's why he's agreed to take us directly to the source. the muzo mines, home to the richest emerald deposits in the world. >> that's river is called the miner's river. tooth right is the town. and to the left are the mines. all these are mines. >> reporter: turf wars here left thousands dead. and while the vi