What is the flint in the context?
I looked it up in dictionary and found a flint is ‘a massive hard quartz that produces a spark when struck by steel’.
Are there any flints on the road? Do the flints lie under the road? In reality I haven’t seen any flint on the road. What I’ve seen on the road are common stones.
What do you think?
Thanks. It’s from A Farewell to Arms by Ernest Hemingway.

the context:
Two carabinieri held the car up. A shell had fallen and while we waited three others fell up the road. They were seventy-sevens and came with a whishing rush of air, a hard bright burst and flash and then gray smoke that blew across the road. The carabinieri waved us to go on. Passing where the shells had landed I avoided the small broken places and smelled the high explosive and the smell of blasted clay and stone and freshly shattered flint. I drove back to Gorizia and our villa and, as I said, went to call on Miss Barkley, who was on duty.

Question

What is the flint in the context?
I looked it up in dictionary and found a flint is ‘a massive hard quartz that produces a spark when struck by steel’. 
Are there any flints on the road? Do the flints lie under the road? In reality I haven’t seen any flint on the road. What I’ve seen on the road are common stones.
What do you think?
Thanks. It’s from A Farewell to Arms by Ernest Hemingway.

the context:
Two carabinieri held the car up. A shell had fallen and while we waited three others fell up the road. They were seventy-sevens and came with a whishing rush of air, a hard bright burst and flash and then gray smoke that blew across the road. The carabinieri waved us to go on. Passing where the shells had landed I avoided the small broken places and smelled the high explosive and the smell of blasted clay and stone and freshly shattered flint. I drove back to Gorizia and our villa and, as I said, went to call on Miss Barkley, who was on duty.

Answer

My reaction to the phrase "clay and stone and freshly shattered flint" is that he means that whatever material was blown up by the shell included these materials.

Flint is a kind of stone. The word "stone" by iself suggests the kind of tough material that is strong, does not break easily, and breaks into compact lumps. Flint shatters easily and produces sharp, flat shards. Prehistoric man produced sharp-edged tools and arrows by chipping flint. He's saying something about the composition and the texture of the material produced by the explosion.

Because flint is very hard and sharp-edged, when it is struck against steel it breaks off tiny fragments. The fragments are so tiny that they spontaneously combust and produce white-hot sparks. Thus it is a traditional way of making fire (and was used in early firearms, "flintlock" guns). But I don't think that's what he means.

Answer

Hi Gordon

Flint can also be a building material (see http://www.theflintwallcompany.co.uk/flint-wall-types.html), but as you will see from the website this material is often found in the southeast of England. Maybe Hemingway was aware of this term and using it to describe the type of rock used to construct roads in that area? To me it does look similar to the types of buildings I have seen in northern Italy.

Chris