坚冰 is a metaphor-heavy noun meaning 'hard ice', but in modern Chinese you almost never see it used literally for actual frozen water except in poetic or journalistic set phrases. Its real job is figurative: it stands for long-entrenched obstacles, deep frozen conflicts, or rigid barriers that are very hard to break. You'll encounter it in political commentary (打破坚冰 'break the ice' on diplomatic standoffs) and news about reform (冲破坚冰 'smash through hardened obstacles'). The literal use (大地上覆盖着坚冰) exists but is rare outside literary description.