United States Geological Survey . http://minerals.usgs.gov/minerals/pubs/commodity/diamond/ . Retrieved 2009-05-05.  ^ a b Spear, K.E; Dismukes, J.P. (1994). Synthetic Diamond: Emerging CVD Science and Technology . Wiley – IEEE . p. 628. ISBN   0-471-53589-3 . http://books.google.com/?id=RR5HF25DB7UC .  ^ Holtzapffel, C. (1856). Turning And Mechanical Manipulation . Holtzapffel & Co. pp. 176–178. ISBN