Black Gemstone
Invokes triple tech. "DarkEternal"
The Black Rock is an accessory in Chrono Trigger. It can be equipped on Marle, Lucca or Magus. When it is equipped and all three are in the same party, they can use the triple tech Dark Eternal. It is located in the city of Kajar in the Kingdom of Zeal in 12,000 BC. To obtain it, you must play Nu's book game to open the door next to his store, revealing the secret room where the black rock is.