The guys at JerryRigEverything recently put the Galaxy Note7 which is the first smartphone with Gorrilla Glass and the results betrayed this vulnerability. While the Gorilla Glass 4 could withstand scratches from objects below level 6 on the mohs scale, the Gorilla Glass 5 is easily scratched by objects on Level 3 which includes objects made from aluminium,silver, gold, iron, steel, glass, sand.
While the Gorilla Glass 5 is a lot less scratch resistant than the Gorilla Glass 4, it would hold up just fine against your fingernails. And since it's a lot more shatter resistant, it would easily survive a few falls onto concrete pavements. Although have a tempered glass screen protector on your brand new device couldn't possibly hurt.