Short answers, pulled from the story.
Flint is a sedimentary cryptocrystalline form of quartz that occurs as nodules within chalk or marly limestone formations. One hypothesis suggests gelatinous material fills cavities bored by crustaceans or molluscs before becoming silicified using dissolved silica from silicious sponge spicules.
Giant flint formations known as paramoudra appear around Europe, especially in Norfolk, England. These formations are distinct geological features associated with the region's specific chalk deposits.
The current earliest evidence of deliberately heat-treated chert comes from Hoedjiespunt 1 in South Africa dating between 130,000 and 119,000 years ago. This technique suggests a strong understanding of pyrotechnology among ancient peoples who heated the stone slowly up to a specific temperature for 24 hours.
Native Americans traded this Ohio Flint across the eastern United States finding its way as far west as the Rocky Mountains because it provided high-quality material for toolmaking. The Ohio flint is the official gemstone of Ohio state formed from limey debris deposited at the bottom of inland Paleozoic seas.
A piece of flint held in jaws of a spring-loaded hammer strikes hinged steel frizzen at an angle creating shower of sparks that ignite priming powder within flintlock firearms. The hard flint edge shaves off a particle of steel exposing iron which reacts with oxygen from the atmosphere to create fire.