**5. Conclusions**

We have reported the preliminary results of an exploration of the mysterious Dzi beads by studying a three-eye bead using laboratory-based optical microscopy and SEM and the advanced synchrotron techniques including XRD, XRF imaging and micro-XANES. The specimen, including the surface, the edges and the interior after slicing, was inspected with an optical microscope and SEM. The crystal structure from a powder specimen, the surface and the edges of a sliced piece were subjected to XRD. They all showed the structure of quartz (SiO2). While there appeared to be a trace of graphite in the former, it was not detected in the latter. XRF imaging also shows that the bead was made of SiO2; in addition to SiO2, there were regular Cu hot spots, as well as Fe, Ca and K at lower concentrations on the circumference of the etched rings. We can conclude, from the material perspective, that the three-eye bead specimen was genuine, and the patterns (dark and light as well as the etched rings), which were apparent to the naked eye, were crafted. The discovery of regular small pits containing copper oxide (CuO) on the circumference, which correlated with the SiO<sup>2</sup> map, and the presence of potassium were consistent with the crafting methods described in the literature [1,2].

Finally, while we have not fully answered the question on the origin of these beads nor expect to do so with a single specimen, in a broader context that will require further studies of representative samples from various regions and times, we are optimistic that the tools and the methodologies introduced here will play a significant role in future studies.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2571-9408/3/3/56/s1, **Figure S1**. The three-eye Dzi beat purchased from a jewelry piece came with an authenticity certificate and a bag. **Figure S2**. (a) The slicing plan for the Dzi bead as seen lengthwise. (b) A depiction of the Dzi bead slicing plan as seen from one end of the bead, looking down the hole that runs lengthwise through the bead. (c) Dzi bead post-slicing. (d) Dzi bead after ultrasound bath. **Figure S3**. Glazing XRD (left panel) of the surface light and dark regions (red dot on the right panel) using 12 keV (1.03 Å) X-rays. Despite the intensity variation, the patterns are identical. **Figure S4**. Cu Kα map recorded based on second order radiation at the Fe K-edge excitation compared with corresponding maps for Si, Fe and Ca.

**Author Contributions:** A.R. conducted most of the lab measurements at Western; R.F. and T.-K.S. conducted measurements at the VESPERS and Q.X., Y.H. and T.-K.S. conducted measurements at the SXRMB; T.-K.S. initiated the project and provided funds for the research. All authors participated in data analysis and discussion. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was supported by the Canada Research Chair (CRC) program and a Natural Science and Engineering Research Council (NSERC) Discovery Grant. Research was in part conducted at the Canadian Light Source which is supported by Canada Foundation for Innovation (CFI), National Research Council (NRC), Canadian Institute of Health Research (CIHR), NSERC, and the University of Saskatchewan.

**Conflicts of Interest:** The authors declare no conflict of interest.
