£1.38 – £3.46 ex VAT
Chert is classified as a sedimentary rock and is a hard cryptocrystalline form of silica. It is found as nodules and bands within the Cretaceous Chalk, with these samples coming from Norfolk in the UK. It is well known for its glassy crystalline texture which allows pieces to be knapped and for this, the rock was used by stone age humans to make various cutting tools and weapons as it often break, leaving sharp edges. The specimens exhibit an earthy brown colour with a waxy lustre and are available in various sizes, which will come supplied in a card tray with an information label.
Chert is a hard, cryptocrystalline silica rock of sedimentary origin. It is often to be found as nodules and irregular masses within sedimentary rocks. It is specifically associated with chalk and marl type limestones and it is believed to have formed as a result of large numbers of echinoderms and sea sponges, the bodies of which were highly siliceous, resulting in the chert forming, which chemically is composed of silica . They can be found in variety of colours from dark grey-black, brown, green through to yellow and white. When found in a black colouration, the rock is often instead referred to as 'flint'. These specimens are however, an earthy brown to yellow colour and show a waxy lustre, often with a white, rough textured outer layer which is usually a layer of chalk. Our examples are from the Cretaceous Chalk beds of Norfolk and are available in three sizes, of which will come supplied in a card tray with an information label.