How did Gollum know that Sting was an elvish blade?

Question

I was watching The Hobbit: An Unexpected Journey and when I came to the Riddles in the dark scene I noticed something weird. When Bilbo points Sting(even though it isn't called that yet) at Gollum, Gollum recoils and says

It's an elvish blade precious but it isn't an elveses is it precious?

My question is how did Gollum know the blade was elvish? To my knowledge he didn't have any interactions with elves before he got the Ring, at least not enough interaction to recognize Sting as elvish craftsmanship. I mean Thorin couldn't even identify elvish blades as elvish it took Gandalf to do that. And after Gollum got the ring he lived in the Misty Mountains until Bilbo showed up. So how did Gollum identity it as elvish?

Answer 1

In The Lord of The Rings Gollum seems to have an affinity (or rather a hatred of) elvish workmanship.

He is in physical pain from the elvish rope.

‘It hurts us, it hurts us,’ hissed Gollum. ‘It freezes, it bites! Elves twisted it, curse them! Nasty cruel hobbits! That’s why we tries to escape, of course it is, precious. We guessed they were cruel hobbits. They visits Elves, fierce Elves with bright eyes. Take it off us! It hurts us.’ ^{Lord of The Rings | The Taming of Sméagol}

And he cannot stomach the elvish waybread

Frodo broke off a portion of a wafer and handed it to him on its leaf-wrapping. Gollum sniffed at the leaf and his face changed: a spasm of disgust came over it, and a hint of his old malice. ‘Sméagol smells it!’ he said. ‘Leaves out of the Elf-country, gah! They stinks. He climbed in those trees, and he couldn’t wash the smell off his hands, my nice hands.’ Dropping the leaf, he took a corner of the lembas and nibbled it. He spat, and a fit of coughing shook him. ‘Ach! No!’ he spluttered. ‘You try to choke poor Sméagol. Dust and ashes, he can’t eat that. He must starve. But Sméagol doesn’t mind. Nice hobbits! Sméagol has promised. He will starve. He can’t eat hobbits’ food. He will starve. Poor thin Sméagol!’ ^{Lord of The Rings | The Passage of the Marshes}

We know that Sméagol's family told tales of ancient history, in one case he talks about the towers built for the siege of Mordor.

‘The old fortress, very old, very horrible now. We used to hear tales from the South, when Sméagol was young, long ago. O yes, we used to tell lots of tales in the evening, sitting by the banks of the Great River, in the willow-lands, when the River was younger too, gollum , gollum .’ He began to weep and mutter. The hobbits waited patiently. ‘Tales out of the South,’ Gollum went on again, ‘about the tall Men with the shining eyes, and their houses like hills of stone, and the silver crown of their King and his White Tree: wonderful tales. They built very tall towers, and one they raised was silver-white, and in it there was a stone like the Moon, and round it were great white walls. O yes, there were many tales about the Tower of the Moon.’ ^{Lord of The Rings | The Black Gate is Closed}

So it perhaps isn't surprising doesn't he recognises and fears an elvish blade.

Answer 2

Bilbo tells him

If you don't mind an answer from the book that is...

'What's he got in his handses?' said Gollum, looking at the sword, which he did not quite like.

'A sword, a blade which came out of Gondolin!'

'Sssss,' said Gollum, and became quite polite. 'Praps ye sits here and chats with it a bitsy, my preciousss.'

_{The Hobbit - Chapter 5 - Riddles in The Dark}

As Gollum then become very meek one can assume he has heard of Gondolin and knows it is elvish, other than just a random sword.

We can assume that Bilbo himself finds out his "sword" is from Gondolin when Elrond examines the swords in Rivendell:

Elrond knew all about runes of every kind. That day he looked at the swords they had brought from the trolls' lair, and he said:

'These are not troll-make. They are old swords, very old swords of the High Elves of the West, my kin. They were made in Gondolin for the Goblin-wars. They must have come from a dragon's hoard or goblin plunder, for dragons and goblins destroyed that city many ages ago.

This, Thorin, the runes name Orcrist, the Goblin-cleaver in the ancient tongue of Gondolin; it was a famous blade.

This, Gandalf, was Glamdring, Foe-hammer that the king of Gondolin once wore. Keep them well!'

_{The Hobbit - Chapter 3 - A Short Rest}

This does lead to the question, where Gollum hear about Gondolin?

Probably from the same source given in Po-ta-toe's answer where he heard about Gondor, and how he learnt about the Battle of Dagorlad.

The Dead Marshes. There was a great battle long ago, yes, so they told him when Sméagol was young, when I was young before the Precious came. It was a great battle. Tall Men with long swords, and terrible Elves, and Orcses shrieking. They fought on the plain for days and months at the Black Gates.

_{The Lord of The Rings - The Two Towers - The Passage of the Marshes}