Comparison of E (IM)-enhanced Sapphires with Surface Diffusion-Treated Sapphires (T)

Diffusion-treated and fancy sapphires enhanced by the new treatment (pastel colors and vivid colors) can be easily distinguished by both gemological properties (Lit. 16 and Internet Lit. 04) and chemical composition as discussed below. For comparison purposes, we use a blue surface diffusion-treated sapphire. The randomly selected diffusion-treated sample (Fig. 65 and Table 7a) does not contain any Beryllium, Ti-concentrations are concentrated at the outer rim, and other chemical elements do not follow Ti-enriched trends. Ti is introduced into the gemstone by diffusion from outside, and only one element is enriched in the rim (Ti concentrations are embedded in chemistry typical of a natural sapphire, with considerable Fe present, as a natural white sapphire was used for the diffusion treatment). The blue color is interpreted as being produced by Fe²⁺-Ti⁴⁺ charge transfer (For further discussions See Table 7a-7c).

Final Conclusion

Over the course of the new E (IM) heating technique the following alterations were made to the original sapphire materials.

1.) Beryllium is diffused into the surface of the gemstones, either restricted to the rim or penetrating the entire sapphire material (See Fig. 41, 45, 49b, 57, 62 and Table 7c).

2.) Unstable color centers are formed in the zones containing Beryllium. They are interpreted as crystal defects (Fig. 4, 5 and 29) not corresponding to fading color centers caused by irradiation (Lit. 19).

3.) The treatment is characterized by a reaction zone, with indications that the atomic structure of the sapphire is completely rearranged (See Cathodoluminescence analysis (Fig. 53)).

4.) The entire set of cations present in the original sapphire material (Fe, Cr, Ti, V, Ga and Mg) is redistributed in the reaction zone over the course of the treatment. In this case study, the cations are depleted in the rim and enriched in an inner rim (in the Madagascar samples), see Fig. 41, 44, 49a and Fig. 57. In the Songea (Tanzania) samples, the entire crystal is involved and the trace elements are enriched at the core (Table 7c).

5.) The color is formed at a particular mix of trace elements, including Fe³⁺, Cr³⁺, and with Mg²⁺ where crystal defects are present (Fig. 26, 27, 28, 29, 30)
continue conclusion

Fig. 65 Sample No.GRS T-Blue Surface Diffusion-treated Sapphire (T).
Craters from scattered LA-ICP-MS Testing.

Fig. 66 Sample No.GRS 12910
Natural Orangy-Pink Sapphire enhanced by new E(IM)-method.Craters from LA-ICP-MS Testing (3 Profiles).

Fig. 67 Sample No.GRS 782
Natural Orange-red Sapphire from Songea (Tanzania) enhanced with the new E(IM)-method.
Craters from scattered LA-ICP-MS Testing.