**1. Introduction**

The origin of Tibetan Dzi beads, also known as "tian zhu" (heaven's pearl) or commonly accepted as Tibetan beads, has always been a mystery. They first appeared between 2000 and 1000 BC in countries surrounding the Himalayas. Authentic Dzi beads are found primarily in Tibet, according to Bolin [1]. There are many legends about how these beads came to be. This is because the Tibetan people believe the beads are of supernatural origin [2]. One story tells of semigods owning them as ornaments. It is said that the beads would be thrown away if they became imperfect in any way. This story explains why Dzi beads are never found in perfect condition [1,2]. Another story is perhaps more well-known and widespread, describing the Dzi beads to be insects. The story tells of a man in the mountains who supposedly threw his hat over such an insect, petrifying it. This petrified insect is said to have been a Dzi bead [1,2]. There are a multitude of other stories that have been told, including the Dzi bead being found in the horns of slaughtered animals as well as in dung [1–3]. The people of Tibet hold these beads in high regard and consider them heritage gems; they are reluctant to sell them for low sums, especially to those in the Western world. Therefore, there has been very little scientific research conducted on them. It is generally accepted, however, that Dzi beads are made from agate, a form of chalcedony quartz with a chemical composition of SiO<sup>2</sup> [1–3].

It is said that the owner or wearer of a Dzi bead is protected from catastrophe. The Dzi bead supposedly wards off evil spirits that might have ill effects on the wearer [1,2]. While being worn, if the bead breaks or chips, it is thought to have served its purpose and has absorbed the energy of a catastrophic event that was intended for the wearer. Thus, the effects of the bead are rendered useless, as it is no longer regarded as "pure" [1,2]. The only time a Dzi is deliberately broken is for medicinal purposes. Doctors in Tibet use powder from the beads mixed with herbs to treat ailments such as epilepsy [1,2]. the bead breaks or chips, it is thought to have served its purpose and has absorbed the energy of a catastrophic event that was intended for the wearer. Thus, the effects of the bead are rendered useless, as it is no longer regarded as "pure" [1,2]. The only time a Dzi is deliberately broken is for medicinal purposes. Doctors in Tibet use powder from the beads mixed with herbs to treat ailments such as epilepsy [1,2].

*Heritage* **2020**, *3* FOR PEER REVIEW 2

supposedly wards off evil spirits that might have ill effects on the wearer [1,2]. While being worn, if

In Ebbinghouse and Winsten's article, they mention three techniques that have been recorded for creating Dzi beads [2]. The first technique for creating a white pattern on a natural stone background involves the painting of an alkali substance onto the surface of the bead and then firing the whole bead [3–5]. The area that has been painted then turns white, and this continues through the surface into the Dzi bead interior [6,7]. The second technique creates a black design on a whitened background. The whitening is done with the aforementioned technique on the entire bead, and then the dark pattern is painted with a chemical such as copper nitrate [8]. Using similar techniques, the third type of Dzi is a black design on a natural stone background [2–8]. It should also be noted that drill bits made of reed in the old days and then copper were used to drill holes in the crafting process. Bolin's book (p. 29) also describes similar treatments in the craft, including darkening with plant sugar and heat, beaching and white line etching with natron (a naturally occurring mixture of sodium carbonate decahydrate, Na2CO3·10H2O, and sodium bicarbonate, NaHCO3, along with small amounts of sodium chloride and sodium sulfate) and protecting the desired areas with grease, clay, etc. [1]. In Ebbinghouse and Winsten's article, they mention three techniques that have been recorded for creating Dzi beads [2]. The first technique for creating a white pattern on a natural stone background involves the painting of an alkali substance onto the surface of the bead and then firing the whole bead [3–5]. The area that has been painted then turns white, and this continues through the surface into the Dzi bead interior [6,7]. The second technique creates a black design on a whitened background. The whitening is done with the aforementioned technique on the entire bead, and then the dark pattern is painted with a chemical such as copper nitrate [8]. Using similar techniques, the third type of Dzi is a black design on a natural stone background [2–8]. It should also be noted that drill bits made of reed in the old days and then copper were used to drill holes in the crafting process. Bolin's book (p. 29) also describes similar treatments in the craft, including darkening with plant sugar and heat, beaching and white line etching with natron (a naturally occurring mixture of sodium carbonate decahydrate, Na2CO3·10H2O, and sodium bicarbonate, NaHCO3, along with small amounts of sodium chloride and sodium sulfate) and protecting the desired areas with grease, clay, etc. [1].

The Tibetan people only regard certain Dzi beads as real or "pure". Dzi beads come in a varied array of patterns, shapes and sizes. A set of patterns that are universally recognized as "pure" are the "eye" patterns, as shown in Figure 1a,b together with representative fakes (Figure 1c) and the three-eye specimen we used in this investigation, Figure 1d,e. Every pattern holds a different meaning and benefit to the wearer [1–3]. The most highly coveted Dzi bead is the nine-eye bead. This bead symbolizes the nine planets, holds the activity of the entire universe and possesses the wisdom of humanity [1,2], and it is said to assist the owner in gaining wealth, good health, success, power, compassion and glory [1–8]. The Tibetan people only regard certain Dzi beads as real or "pure". Dzi beads come in a varied array of patterns, shapes and sizes. A set of patterns that are universally recognized as "pure" are the "eye" patterns, as shown in Figure 1a,b together with representative fakes (Figure 1c) and the threeeye specimen we used in this investigation, Figure 1d,e. Every pattern holds a different meaning and benefit to the wearer [1–3]. The most highly coveted Dzi bead is the nine-eye bead. This bead symbolizes the nine planets, holds the activity of the entire universe and possesses the wisdom of humanity [1,2], and it is said to assist the owner in gaining wealth, good health, success, power, compassion and glory [1–8].

**Figure 1.** Dzi bead patterns. (**a**) The most precious Dzi beads. (**b**) Beads that are of lesser value than (**a**) but are most recognized and worn as traditional ornaments [2]. (**c**) Dzi bead imitations. Left to right: plastic with metal core, polymer clay and painted aluminum [4].(**d**,**e**) Photograph of the Dzi bead used in this study, showing a one-eye pattern on one side and a two-eye pattern on the opposite side. The middle column in (**b**) depicts what the three-eye bead looks like when unfolded. **Figure 1.** Dzi bead patterns. (**a**) The most precious Dzi beads. (**b**) Beads that are of lesser value than (**a**) but are most recognized and worn as traditional ornaments [2]. (**c**) Dzi bead imitations. Left to right: plastic with metal core, polymer clay and painted aluminum [4]. (**d**,**e**) Photograph of the Dzi bead used in this study, showing a one-eye pattern on one side and a two-eye pattern on the opposite side.The middle column in (**b**) depicts what the three-eye bead looks like when unfolded.

Tibetans have created criteria for what makes a Dzi bead valuable. As mentioned, the bead must have a desirable pattern that is considered "pure". A Dzi bead must possess a round cross-sectional shape and not appear thin [1,2]. As noted above, the Dzi bead must not be broken or chipped, as this is said to reflect the fact that it has already served its purpose. When held up to the sun, the bead should be translucent or reveal any internal flaws with the pattern, although there are exceptions Tibetans have created criteria for what makes a Dzi bead valuable. As mentioned, the bead must have a desirable pattern that is considered "pure". A Dzi bead must possess a round cross-sectional shape and not appear thin [1,2]. As noted above, the Dzi bead must not be broken or chipped, as this is said to reflect the fact that it has already served its purpose. When held up to the sun, the bead should be translucent or reveal any internal flaws with the pattern, although there are exceptions [1,2]. Tibetans know how to identify a genuine Dzi bead from a fake; however, imitations have been created because these beads are so valuable.

The demand for Dzi beads in Asian regions has increased and spurred the production of replicas. Some replicas have such minute details that they must be observed more closely under a microscope or cut open to reveal if they are fake. In most cases, it has been identified that a replica weighs less than the original [4]. Other replicas are fitted with a metal center to imitate the weight of the real beads. Dzi bead replicas are usually made of plastic, glass or a light metal such as aluminum; examples are shown in Figure 1c [4].

The objective of this work is to investigate the pattern, the elemental and chemical composition as well as the structure of a three-eye Dzi bead using conventional laboratory techniques, such as optical microscopy and scanning electron microscopy (SEM), and advanced X-ray techniques from a synchrotron source. X-ray diffraction (XRD) reveals the crystal structure and, hence, mineral formation of the bead; X-ray fluorescence (XRF) reveals its elemental composition; and X-ray absorption near edge structure (XANES) reveals the local structure of a selected element of interest. Using a micro-X-ray beam, we can conduct microscopy and microanalysis of the different patterns of the specimen. We have gained considerable experience over the years in the research and development of these techniques [9] and are encouraged by our recent success in retrieving high-resolution images from badly tarnished daguerreotypes [10–12], the first public photographs in human history. The applications of X-rays from synchrotrons in art and archaeology have also been reviewed recently [13]. Based on these techniques, we will attempt to investigate if the specimen is genuine or fake, if the pattern is natural or man-made and if there is any evidence for the crafting methods we noted above, as described by Bolin and Ebbinghouse and Winsten [1,2]. We show below that we can provide some positive answers for these questions in this preliminary study using synchrotron radiation.
