Luminous Powder For Watch Faces. This is a new vial of luminous powder. Great for watch faces. This powder illuminates the hour hands, minute hands or markers in the dark so you can tell time in insufficient light. Contains approximately 1 gram (0.035 oz). We work hard to update our descriptions and pictures of our merchandise. As part of a process of ongoing innovation by our suppliers, newer versions of the item shown may be shipped before we are able to complete an update. As a result there may be a slight variation in color and design.