Now showing items 20-39 of 90

    • Epidote 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 1994)
    • False forms 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 1989)
    • Feeling minerals 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 2000)
    • Field spar 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 2004)
    • Fire of opal 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 1993)
    • Floating copper 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 1997)
    • Geology and the growth of downtown Stillwater 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 1993)
    • Graphic granite 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 2008)
    • Green rust and invisible gold 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 2004)
    • Greenstones, greenstones and green stones 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 2004)
    • Hibbingite - swimming pool mineral 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 1994)
    • How amethyst cathedrals form 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 2007)
    • How do dendrites form? 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 2008)
    • How fast can crystals grow? 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 2004)
    • Hunting the source of Georgia tektites 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 2005)
    • Ice mineralogy 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 1989)
    • Kaali Meteorite catastrophe 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 2002)
    • Lake full of lead 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 1995)
    • Lazulite or Lazurite? 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 1999)
    • Luster of pearls 

      Cordua, William S. (William Sinclair), 1947- (St. Croix Rockhounds, Stillwater, MN, 1997)