Flint and chert were employed for knives, etc., but with none of the marvellous skill and artistry of the predynastic Egyptian flint-knapper; the early Babylonian used comparatively simple flakes and the wonderful serration of the Egyptian knives was unknown to him though he made the saw-blades.
The figures for the more important minerals are as follows: Gold ore, manganese ore and uranium ore are produced in small quantities, and the list of minerals worked in the United Kingdom also includes chalk, lead, alum, phosphate of lime, chert and flint, gravel and sand, zinc ore, gypsum, arsenic, copper, barytes, wolfram and strontium sulphate.
Thus in the microcrystalline chalcedony the lustre is waxy, the fracture fibrous to even, and the external form botryoidal or stalactitic flint and chert are compact and have a splintery fracture: jasper is a compact variety intermixed with much iron oxide and clay and has a dull and even fracture.
In limestones of various kinds it occurs as nodules and bands of chert and flint, being in this case of organic origin.
The fossils from the Rhaetic beds belong to the Avicula contorta zone, those from the Lias to the Ammonites angulatus zone, while the blocks of limestone with chert contain Inoceramus, Cretaceous foraminifera and other organisms. The materials yielding these fossils are embedded in a course volcanic agglomerate which gives rise to crags and is pierced by acid and basic igneous ricks.
In the Cambrian limestones, as in their more recent analogues, layers and nodules of chert and phosphatized material are not wanting.
The Millstone Grit contains fragments of chert which can only have come from the waste of the earlier limestones.
Celts, of the usual late neolithic type, were generally of green jasper; hoe-blades (looking almost exactly like palaeolithic haches a main) of chert or coarse limestone; hammers of granite; mace-heads, of identical type with the early Egyptian, of diorite and limestone; nails of obsidian or smoky quartz, often beautifully made.
In the limestone was found the flint or chert used for weapons and instruments in early times.
The beds of chert are utilized in the pottery industry, and some of the harder and more crystalline limestones are beautiful marbles, capable of taking a high polish.