Teacher background information

Traditionally, the mineral quartz and fine-grained quartz-rich rocks such as silcrete, chert and quartzite, as well as hard volcanic rocks such as basalt, were important resources for Aboriginal and Torres Strait Islander peoples. Traditional geological knowledge enabled suitable rock types to be identified, quarried or mined, and worked into a variety of sophisticated tools. Respective Aboriginal and Torres Strait Islander groups have their own geological terminology.

This elaboration provides an opportunity for students to explore Aboriginal and Torres Strait Islander peoples’ traditional knowledge and use of different rock types. Aboriginal and Torres Strait Islander groups across Australia produced a variety of stone tools. Stone tools, and the debris formed during the production process are collectively classified by archaeologists as stone artefacts. These artefacts are the most common form of archaeological evidence found in Australia and continue to be used to confirm the antiquity of human presence in Australia. Traditionally, stone tools have been of vital importance to Aboriginal and Torres Strait Islander peoples. They have been essential in hunting and gathering food and in its preparation and processing. Stone tools have also been used to make new stone and wooden implements and ceremonial objects.  

Aboriginal and Torres Strait Islander peoples have a deep understanding of the properties of various minerals and use different rock types for different applications. Through direct observation and through trial and error, First Nations’ Australians recognised that igneous rocks such as basalt or volcanic greenstone, tend to be very hard minerals with high tensile strength which make them ideal materials for stone axes.  

More commonly, sedimentary rocks such as sandstone, or metamorphic rocks such as quartzite, were preferred to manufacture grindstones and millstones for other food sources, as they provided a more abrasive surface. However, the Bama people of northern Queensland chose an unlikely stone type, metamorphic slate, as a grindstone in processing toxic cycad kernels for producing an edible source of carbohydrates. As slate has a smooth and generally non-abrasive surface that is not particularly suitable for grinding food, cross-cuts were incised into the stone to achieve the intended effect. It is believed that this rock type was chosen for its mildly hydrophobic properties. The Bama people understood that this property of metamorphic slate prevents the accumulation of toxins in the grinding tool.  

Other recorded uses of sedimentary rocks by Aboriginal and Torres Strait Islander peoples include naturally occurring clay earth pigment ochre, which is a mixture of ferric oxide and varying amounts of clay and sand. For thousands of years, in many regions throughout Australia, red ochre has been the most highly prized and important pigment for use in cosmetics, body and artefact decoration and rock painting.  

Historically, the distribution and location of valuable rock deposits were well known to Aboriginal and Torres Strait Islander peoples and played a significant role for access and trade between groups. For example, ochre and stone of one sort or another can be found almost anywhere on the Australian continent. However, the ochre and stone deposits that were, and continue to be, exploited by Aboriginal and Torres Strait Islander peoples were of particularly high quality and traded over large distances. In the case of ochre, the most highly valued properties relate to its refractive qualities that create the shimmering effect under fire light, and its low acidity which does not irritate the skin. The optical properties of ochre are still highly sought after in contemporary industries, such as the cosmetic industry, for their exact same use. 

After identifying valuable rock types and their locations, Aboriginal and Torres Strait Islander peoples developed sophisticated extraction techniques for these important resources. The two most common of these techniques are quarrying and mining. There are several hundred recorded Aboriginal mineral and rock extraction sites in eastern Australia alone. While many of these sites are open cut, some, such as that at Wilgie Mia in Western Australia, provide examples of extensive and deep underground mining. Wilgie Mia is known as the world’s oldest continuous mining operation.  

This elaboration will assist students in gaining an understanding of sedimentary, igneous and metamorphic rock types. By learning about Aboriginal and Torres Strait Islander peoples’ traditional geological knowledge, students gain an appreciation of the antiquity and sophistication of this knowledge. They also gain a deeper understanding of how Australia’s First Nations peoples exploited the useful properties of rock and understood the distribution of valuable rock types and sites. Students gain an insight of how Aboriginal and Torres Strait Islander peoples developed extraction techniques and how First Nations’ geological knowledge has contributed to contemporary society, for example, in the production and exportation of iron oxide pigments.