Damaged worktop

Is there any way to repair a chip to the top edge of a dark grey granite effect worktop? The chipboard core is exposed and I mainly want to seal it to prevent water penetrating, but an approximate colour match would help to disguise the damage. Thanks for any help.

 

Nail varnish? Maybe. I would probably need black. Don't know any Goths.

Yes, loads of scrap. I think I'll try big all's suggestion.

Thanks.