Meteorite from Mars?
"Scientists have recently concentrated on Antarctica as the best place to find meteorites.  Here meteorites are:
Less likely to shatter striking ice than rock.
Easier to spot on ice than on dirt.
Less likely to be contaminated by earth-life.
"Our particular rock, ALH 84001 has a thin, dark, glassy coating, the distinctive fusion crust from its fiery descent thru the atmosphere.