An rare 'old mine' bipyramid shape mineral specimen from Kashmir, India. The color is a soft medium 'open' blue after low temperature treatment.
The majority or 95%+ of ruby & sapphire in the world are thermally enhanced. The heat treatment enhances the color permanently by reducing the iron which couples with titanium creating an intervalent charge transfer, thus increasing the blue color.
These are the first heated Kashmir sapphire in the world because the rough is not available and mining has mostly stopped in the past 100 years. The stone was heated by Eddie Cleveland ~1200C in a reducing atmosphere.