Corundum Internal Diffusion Crystal. Colorless Montana Missouri River sapphire rough with rutile crystal inclusions that when heated release titanium causing the blue haloes. Montana Missouri River sapphire courtesy of Sid Tucker. Internal Diffusion Crystal. Colorless Montana Missouri River sapphire rough with rutile crystal inclusions that when heated release titanium causing the blue haloes. Montana Missouri River sapphire courtesy of Sid Tucker. Rutile in a Burmese ruby. The rutile is illuminated by fiber optic light. Sapphire Surface of a Montana Missouri River sapphire. Courtesy of Sid Tucker. Montana Missouri River Sapphire. The reddish orange included crystals are likely to be rutile. Courtesy of Sid Tucker. Montana Missouri River sapphire crystal. The reddish orange included crystals are likely to be rutile Courtesy of Sid Tucker. Crystal and rutile silk needles. Included crystal with rutile 'silk' needles inside of an unheated ruby. Triangular growth on the surface of a Montana sapphire. Courtesy of Sid Tucker Angular growth in a Ramaura synthetic ruby. Triangular growth on the surface of a Montana sapphire. Courtesy of Sid Tucker.