Stone Type: Chert

Chert MacCorkle 1

Chert is a sedimentary rock composed of microcrystalline quartz.  It usually formed by the precipitation of silica into other sedimentary rocks, occurring as nodules or layers in limestone.  It forms when tiny organisms extract pure silica from ocean water and use it as body armour or skeletons.  When the organisms die, their skeletons dissolve and form a siliceous ooze, which eventually precipitates, coalesces, and recrystallises as the surrounding limestone rock is formed. 

Leilira with bark sheath 1

Macroblade (Leilira) Knife

Handaxe, Boulia

Handaxe

Biface, Mark Moore 2018

Modern Art, Mark Moore

Blade, Europe AIA

Blade

Flake, Italy AIA

Flake

Timor Tanged Point

Timor Tanged Point

Adze blank, Song Gupuh

Stone Adze Blank

Aterian point 2 17 Jul 2023

Aterian Point

Biface handaxe Camooweal

Handaxe

Single platform core NT Darrell Lewis

Single Platform Core

Retouched flake VRD Darrell Lewis

Retouched Flake

Retouched flake Tjimari Lewis

Retouched Flake, Tjimari

NT Triangular Point reverse

Northern Territory Triangular Point

Macroblade point, Helen Springs NT

Macroblade Point

Macroblade point, Wave Hill 1

Macroblade Point

Single platform core rock show

Single Platform Core

Hammerstone Ukraine

Hammerstone

Adze blank stitched from Indonesia

Stone Adze Blank

Levallois Nubian YP

Levallois Core

Burren adze with resin 4

Hafted Retouched Flake

Marine cherts sometimes contain fossils of organisms like diatoms and radiolarians, as well as sponge spicules.  Petrified wood is a form of chert where the silica has replaced the structure of the fossil.  The internal structure of chert is amorphous and lacks layering, which makes it ideal for stone-flaking.  It occurs in a wide variety of colours, and most varieties respond well to heat-treatment to improve the material’s flaking characteristics.  Chert is a general category which includes folk classifications like flint, chalcedony, opal, novaculite, porcellanite, and jasper, and many archaeologists prefer to use the folk classifications when describing artefacts.