heat treatment method to convert deguna stones to padparadscha : Scholars' Press : 9786138831488 : 6138831489 : 22 Oct 2020 : As a traditional heat treatment practice, red and blue combined deguna stones are converted to pink sapphire or ruby around 1,200 degrees of Celsius under oxidizing ambient air state inside the Lakmini furnace. Under these conditions, already available red tone due to chromium (III) ions is highlighted since fading of blue colour occurs because of the dissociation of ferro - titanium bi - particle. This book introduces a novel heat treatment technique to convert pale reddish blue colour deguna stones to padparadscha sapphire by further oxidizing these dissociated Iron (II) ions into Iron (III) ions to arise yellow hue within the red tone enriched corundum host. By this heat treatment technique, pale reddish blue colour deguna stones can be successfully converted to padparadscha sapphires and golden sapphires at 1,400 degrees of Celsius under high oxidizing ambie