If you ever see this emblem on a gravestone, you will know the individual it memorializes was connected to the Ancient Arabic Order of the Nobles of the Mystic Shrine, commonly referred to as Shriners. This organization was established in 1870 and is an extension of Freemasonry. All Shriners must be Masons. To learn more, visit the A.A.O.N.M.S. page at Wikipedia or the official web site of the Shriners of North America.
Note: The photo is from the gravestone of Thomas Harris Walker (born 16 October 1926, died 30 April 1953) at Magnolia Park Cemetery in Warner Robins, Houston County, Georgia.