Inactive Volcanoes

These would be a variant of the normal mountain biome that would give hint towards an extinct volcano. Lush and full of life, this biome would have igneous rocks generation around the place, similar to mossy cobblestone in big tree taiga biomes. These rocks would include obsidian and other volcanic glasses, granite, andesite, and basalt. There could also be basalt cliff faces on some of these mountains, like in Iceland. These mountains would feature a volcanic tube with igneous rocks littering the inside. This would fit in the theme of the caves and cliffs update and provide a new type of terrain to explore. This would provide a designated area for the stone variations which will clean up caves, provide lore for the game, and if you wanted to get really special, maybe a mob that lives in the volcanic tubes. It would be nice if this idea didn't take away from basalt deltas, despite being from a similar idea.