I came across this rock when it was included as part of an auction. The surface is dull black in color. The rock is pyramid shaped with the dimensions 5"x5"x5". Compared to other rocks of its size it is extremely heavy. Total weight is about 18lbs. After chipping a corner of the rock off, the interior revealed a lustrous, metallic, silver color. It is very hard and scratches a knife blade. Here's a link to some pictures.
http://pg.photos.yahoo.com/ph/kordic1008/album?.dir=/739a&.src=ph&.tok=phQd3uDBicNh0EoH
I appreciate any info.
Thanks
GeologyRocks