Where can i get flint rocks to create sparks in new zealand?

Question

I would like to know where to get flint rocks suitable for making sparks and what to use to strike the flint, i've checked the beach and i know a nearby river (i haven't looked properly at the beach)and it would help if you describe what flint looks like

thanks

Answer 1

"Flint" for starting fires refers to any particularly sharp and durable stone.  The process itself works not by striking two rocks together, but rather by striking a rock against a piece of iron or steel.  The sharp edge of the rock shaves metal filings from the steel, which combine with atmospheric oxygen and friction from the rock to glow hot enough to light tinder (thin shavings of flammable material with enough surface area to support combustion, like hamster cage shavings or dryer lint).

Any hard rock will do, and if a sharp one cannot be found, a round rock can be broken to produce a sharp edge.

Answer 2

I like marnevel's drift, but some clarification is needed.

1) Most rocks seem "hard," but the reason that chert is used is because it's harder than the iron or steel.  Many rocks, including limestone, some sandstones, and even marble, do not have an effective hardness greater than that of steel, and will therefore fail as "flints" for this purpose.

2) Even most hard rocks will fail to break off the tiny ribbons of iron that are desirable for firestarting.  This is because they lack the ability to be sharpened easily to a fine edge.  Chert, on the other hand, is a material that naturally breaks to a knife-edge.

((3) Instead of using the pieces of iron to get the fire started, you can use a spark itself, which can be generated by striking any hard rock with another rock composed of sufficiently large crystals of quartz.  See below link to read more about this.))

OK, so, really we're back to the question of where to find chert in NZ.  Well, check out any geological map and see where any formations called "chert" or "cherty limestone" or "novaculite" occur.  Go to outcrops in any such area, and you should easily be able to find what you need — just look for the rocks that naturally fracture to a knife-sharp edge.  The below link will give you a start, but it looks like even more detail — at the Formation level — will be needed in order for you to be successful.

Actually, here's one confirmed occurrence for you: the Amuri Limestone of Marlborough.  See final url below for lots of details.