It doesn't look like gold to me, but that doesn't mean it isn't, You say you scraped it with a knife and it didn't flake, did the knife do anything to the specimen, a scratch, scrape mark etc.?
Try pushing the point of the knife into it, if it's gold it should at least make a [FONT=Helvetica Neue, Helvetica, Arial, sans-serif]noticeable[/FONT] mark/indent where the point of your knife is pushed into the specimen, gold is malleable, a soft metal and as such will be marked by enough pressure from a steel knife blade.