PBR Rock Diamond Stone Low-poly 3D model is available on CGTrader for $7. Original author: CgiArt. Specs: 7168 polys, 6307 verts.
OBJ (OBJ, filesize: 723 KB), FBX (Autodesk FBX, filesize: 863 KB), MAX (Autodesk 3ds Max, filesize: 1.6 MB), TEXTURES (Textures, filesize: 430 MB)