Lava Rock

The Lava Rock (溶岩) is a mysterious item featured in the ninth part of the JoJo's Bizarre Adventure series, The JOJOLands.

Summary
Samples of cooled ʻAʻā lava rock which is analyzing in his villa in Hawaii. He keeps two particular samples in a safe, next to his diamond. The lava is extremely precious and Rohan is confident that the two small samples in his possession are the only ones in existence. Jodio crushes one of the samples to blackmail Rohan, leaving only one left. Rohan secretly reveals to Jodio that he can become extremely rich if he handles the lava with care, due to it containing a hidden "mechanism". Rohan lets Jodio take the remaining sample with him.

Jodio and Dragona later discover that the lava gathers valuable material toward it, such as the diamond, bank notes, and Rohan's Pink Dark Boy artwork.