Petropia

Petropia is a craggy, geode-like planet where silicon-based beings evolved to build a complex society of separate underground kingdoms. The smaller asteroids near it might be moons. While there are several different gem-based races, from ruby to emerald to sapphire, each with its own distinct abilities and culture, most Petrosapiens (Diamondhead's species) now coexist peacefully. After several centuries of warfare, a giant hole was ripped in the sky, revealing a universe far beyond Petropia's heretofore self-contained existence. As its recently enlightened inhabitants have now begun to turn their focus off-world, the rest of the galaxy holds their breath, waiting to find out if these crystalline warriors will wage war or come in peace..

Petropia was the homeworld of the Petrosapien species,and crystalosapiens (Chromastone) until it was destroyed by Vilgax.

But Petropia was revived with all it's inhabitants in The Secret of Chromastone, formerly by Sugilite, but the actual mission was completed by Ben as Diamondhead.