Fig. 5From: A Raman micro-spectroscopy study of 77,000 to 71,000 year old ochre processing tools from Sibudu, KwaZulu-Natal, South Africaa Both sides of the grindstone from layer BS square B4a; micro-photograph showing, b red residues and c smoothing features and d Raman spectra obtained on the grindstone: (A) amorphous carbon, (B) haematite, (C) quartz, (D) feldspar, (E) manganese oxide and (F) mixture of haematite and maghemiteBack to article page