The Stone Age: Found Objects

Question 1

What were the common stone tools?

Answer 1

Tools made from materials that are readily fractured/knapped; e.g. flint/chert

Question 2

What is obsidian?

Answer 2

Was the preferred material; a metamorphic form of volcanic glass; was not available in UK so was/is sourced form Melos

Question 3

What is flint?

Answer 3

A type of chert; SiO2 (essentially quartz)

Question 4

Where is flint found?

Answer 4

In sedimentary rocks, e.g chalk and limestone

Question 5

How is it theorised flint was formed?

Answer 5

Chalk was formed from deposition of dead organism (e.g. coccoliths, which had shells made from CaCO3), which was sedimented to the sea floor ~75 million years ago; in top 5m, a layer of biogenic silica was produced by sponges; silica precipitated out at an oxic/anoxic boundary @~10m below sea bed; as flint nodule sank through sea floor become purer and contained less defects, e.g. fossils

Question 6

Why are defects in flint bad?

Answer 6

Might interfere and divert direction of fracture passing through the material during knapping of flint into shape

Question 7

How many years ago was flint used?

Answer 7

~5000 years ago

Question 8

How far down could flint mines be?

Answer 8

Up to 14m (Grimes Graves, Norfolk); best flint at base of layer

Question 9

How is flint shaped?

Answer 9

Hitting core causes sinusoid waves through flint, and flint fractures in the shape of the sinusoidal wave: first peak of shockwave is biggest and occurs immediately below where blow was struck (the platform), creating the largest ripple-shaped fracture (bulb of percussion); size of peaks diminish through the flint, forming rippled shapes in the flint’s fracture (radial ridges)

Question 10

What is the characteristic sign on a man-made flint?

Answer 10

The bulb of percussion

Question 11

What structure is flint?

Answer 11

Cryptocrystalline

Question 12

What is a cryptocrystalline structure?

Answer 12

Is intermediate of: brittle and ductile; amorphous and structured. Contains no grains or sheer planes. Has quasi-crystals

Question 13

Why is it good there are no grains or sheer planes in flint?

Answer 13

So when struck, doesn’t fracture along these grain boundaries or sheer planes; instead fractures in a manner directed by the application of force (a conchoidal fracture)

Question 14

How is flint-working promoted?

Answer 14

By using a deer antler as a soft hammer; pressure flaking; heat treatment

Question 15

What does pressure flaking do to flint?

Answer 15

Applies a point tool to the flint with increasing pressure until flint fails/fractures

Question 16

What does heat treatment of flint do?

Answer 16

Improves flakeability (300-400 Celsius for several hours)

Question 17

What is ductile failure?

Answer 17

Substantial plastic deformation around the crack up

Question 18

What is the difference between amorphous and crystal structure?

Answer 18

Amorphous has an absence of structure (short range order), whilst crystal has long range order

Question 19

What is transgranular and intergranular fracture?

Answer 19

Transgranular is fracture through the grains, whilst intergranular is fracture following the shape of the grains

Question 20

How was gold a found object?

Answer 20

Inert, so found in native state; extremely ductile so could be hammered out to form gold leaf

Question 21

What crystalline structure does native copper have?

Answer 21

Face centre cubic

Question 22

Is native copper polycrystal or single crystal?

Answer 22

Polycrystal, so may have variations in properties even if is a seemingly homogenous material

Question 23

When was native copper first found/used?

Answer 23

During the chalcolothic period