Hope Diamond Phosphorescing (IMAGE) Smithsonian Caption The Hope Diamond phosphoresces a fiery red color when exposed to ultraviolet light. Credit John Nels Hatelberg Usage Restrictions Please include the photo credit when using this photo. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.