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CFG Heritage offers non-destructive X-Ray Fluorescence (XRF) to geochemically characterise stone artefacts. XRF can be used to determine an artefact’s raw material and, in many cases, source.

Obsidian (matā, tūhua)

Obsidian sourcing is the best-known use of XRF in the archaeology of Aotearoa. Obsidian can be very closely matched to specific geographic sources, and can be used to show how the material, and people, were moving around the landscape and how people were interacting with each other and how these interactions changed over time.

Adze stone

Stones such as basalt (ōnewa), greywacke, argillite (pakohe) and gabbro were commonly used for making adzes (toki) as well as taonga such as stone lures, etc. These can’t currently be as closely sourced as obsidians, although some stones such as Tahanga basalt have been well studied. Work is under way to characterise the basalts and greywackes of Tāmaki. Others can be assigned to a broad region, e.g., Nelson-Marlborough argillite, and future work will help narrow down these geographic regions down.

Historic bricks

Work is underway to characterise the 19th century ceramic industry of colonial Auckland. Preliminary analysis shows regional differences between brickworks in West Auckland (e.g., Avondale, Waitakere and Whau) and South Auckland / North Waikato (e.g., Drury and Huntly). Reference bricks from other brickworks in the Auckland region (e.g., Arch Hill, Whitford and Newton) and beyond (Palmerston North, Christchurch and Wellington) are being added to the database as they become available.

Geochemical analyses offered by CFG Heritage report the results of the geochemical analyses as elemental concentrations and, where possible, raw material types and geographic sources of artefacts