The core also appears to be surrounded by a relatively thin, hard shell of Iron Sulfide, underneath another relatively thin silicate mantle somewhat similar to Earth's (NASA MESSENGER press release and featured image; Smith et al, 2012; Mike Wall, MSNBC News, March 21, 2012; and Paul Rincon, BBC News, March 21, 2012). (solstation.com)
Or it might be associated with chemical reactions between the outer core's iron - rich fluid and the crystalline silicate mantle.» (sciencedaily.com)
Unlike Earth, Mercury has only a relatively thin silicate mantle and crust, only 500 to 600 km (311 to 373 miles) thick. (solstation.com)