i just don't know, the image i posted looks oversaturated now.Personally I figured they were black, and it's a combination of the lighting in the room and the age of the prop that's making the colour look a bit purple.
On that note, it's been really interesting to see people post screenshots from the actual film to see how much the colour of this little dude has changed over the years! I'm definitely rethinking the paintjob of my own Goblin after seeing this thread.
Here's another couple of images to compare, all coming from this blog post. At least in these images they read pretty strongly as black to me.
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maybe it was black initially but has ages to a purplish hue?
trying to find a pinstripe with 6mm stripes is not easy, i might have to paint the stripes on at this rate.
i would say as the screen prop stands now the head and body has lost 95% of its original colour, i will definitely be going for golds, brasses and silvers.
cheers