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Obsidian is a naturally occurring volcanic silicate glass produced when highly viscous felsic lava cools rapidly through the glass transition temperature, not allowing sufficient time for crystal growth. Obsidian was a popular raw material in prehistory because its amorphous and isotropic nature means that little force is required to produce conchoidal fractures of predictable shapes and sizes and...
Obsidian is a natural volcanic glass which is amorphous and isotropic. These characteristics allow it to be easily shaped as little force is required to produce conchoidal fractures of predictable forms and sizes. A class of obsidian artefacts known as ‘stemmed tools’ have been found in locations situated across lowland Papua New Guinea and have been approximately dated to the early and middle Holocene...
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