What historical cultures pioneered abstract sculptures using unworked stone?

Abstract sculptures crafted from unworked stone are among the earliest forms of artistic expression, with several ancient cultures leading the way. One of the most notable examples comes from the Neolithic period, where cultures like the Cycladic civilization in the Aegean created stylized figurines from raw marble. Similarly, the indigenous peoples of the Americas, such as the Olmec, used unshaped stones to represent deities and spiritual figures. In Africa, the Nok culture of Nigeria produced abstract terracotta and stone figures, while prehistoric European megaliths like those at Stonehenge demonstrate a reverence for natural stone forms. These cultures laid the foundation for abstract art, emphasizing simplicity and the inherent beauty of unworked stone.