On the possible contribution of meteoritic metal to Ni-rich Indonesian kris daggers: Comparing original daggers and newly forged analog objects

The “Weltmuseum Wien” owns a large collection of kris daggers from Indonesia. These objects are famous for their metal blades consisting of numerous layers made by a complicated forging process involving repeated folding and welding of the individual layers. There is a widespread belief that some krises were manufactured by adding meteoritic nickel–iron from the Prambanan meteorite that fell in Central Java and is known since the late 18th century. In our study, we investigated a selection of five Ni-rich krises from this collection with the aim to identify in their blades nickel–iron from Prambanan or another iron meteorite source. To obtain a better insight into the forging process, we investigated analog objects that were produced by a forging procedure similar to the one applied in the production of original krises and by using iron meteorite material from the meteorites Campo del Cielo and Gibeon as admixture. These investigations were performed by nondestructive analytical techniques, including handheld X-ray fluorescence (HH-XRF) analysis, scanning electron microscopy (SEM), and electron microprobe (EMP) analysis. The original daggers were investigated by HH-XRF and micro-X-ray fluorescence (μ-XRF) analysis, as well as by portable laser ablation (pLA) subsampling followed by trace element analysis using inductively coupled plasma mass spectrometry (ICP-MS). By comparing the data obtained for both materials, we demonstrate that the main difficulties in identifying the presence of a meteoritic component in the kris daggers are due to the exclusive use of (quasi-)nondestructive methods in combination with locally varying surface heterogeneities, resulting from contamination, corrosion, and etching features. We also show that the presence of significant amounts of Ni and Co (in the wt% range) in a premodern kris dagger does not imply that it was manufactured with an admixture of meteoritic metal. We found that among the five krises investigated, only a single dagger (no. 900382) was manufactured with the possible admixture of nickel–iron from the Prambanan iron meteorite, as it contains high concentrations of siderophile elements and has a Ni/Co ratio comparable to that of the meteorite.