a grating sound <as of> something heavy being pushed...

[park sang joon]

As I reached level ground and hurried toward the place of the action, I passed pockets of ground mist, stirred slightly by a breeze from out of the west, snaking silvery, about my ankles, I heard a grating, crunching sound as of something heavy being pushed or rolled over a rocky surface.
["The Courts of Chaos" of The Great Book of Amber by Roger Zelazny]
I'd like to know "of" means "about" here.
Thank you in advance for your help.

 

[se16teddy]

'Of' indicates a characteristic here. It was the sound of a heavy thing. Heavy things being pushed over a rocky surface have a typical sound, and this sound was like (as) that one.

 

[park sang joon]

Thank you, se16teddy, for your very helpful answer.
Then, I'd was wondering if in most cases, "of" of "as of" indicates characteristic of the object "of."