As the first total solar eclipse since 1979 in the contiguous United States approaches this summer, the USPS will release a unique, new stamp.
The total solar eclipse stamp will be printed with thermochromic ink so that when you rub it, the image of a blacked-out sun transforms into a detailed photo of the moon that’s blocking it. Then, it reverts into the image of an eclipsed sun.
Here’s what it looks like, before and after you touch it:
Of course, special stamps mean special care: Because thermochromic ink is vulnerable to UV light, the post office recommends keeping the stamps away from sunlight.
The “forever” stamp will be sold starting June 20, with an option to buy an envelope to protect it from UV light. The stamp pane, or the back of a sheet of stamps, will feature a map showing the path of the eclipse across the United States on Aug. 21. The eclipse will be visible, at least in part, in 14 states, from Oregon to South Carolina.
For more on the astronomical event, visit NASA’s Total Eclipse website.