Once in a blue dune…On the floor of the Lyot Crater on Mars lies a field of dunes. One particular dune, seen in this January view, appears turquoise blue in enhanced color & is made of a different composition than the surrounding dune field. Take a look: https://t.co/zeVqWJHO1i pic.twitter.com/PlMNFI4VQr

— NASA (@NASA) June 21, 2018
.....