natural london blue topaz oval cut in the turning ... Color reflections of precious crystal minerals, fine cut sapphire. Jewellery gemstones. Blue Light Magical bokeh abstract background. Abstract ...

Some stones exhibit the phenomenon known as color change, most often going from blue in daylight or fluorescent lighting to purple under incandescent light. Sapphires can even ... is a very common ...

Light elements, such as beryllium at low ppm levels ... This information should enable gemological laboratories to distinguish blue sapphires containing natural beryllium from beryllium-treated blue ...