While we were working on the mystery of the fading amber cabochons described in the Summer 1993 Lab Notes section we received a necklace of baroque amber 'nuggets" (figure 1) that had many of the characteristics of the previously described specimens. Specifically, the "nuggets" also fluorescent orange to long-wave U.V. radiation in the brown areas and blue in the nearcolorless areas. A few beads had planes of tiny bubbles near the surface, and many showed heat induced "sun spangles." As with the cabochons, the color of these beads also appeared to be confined to the surface, although wherever a stress "spangle" broke the beads were carefully shielded from the surface, the brown color has penetrated it, contrasting markedly with the colorless appearance of those spangles that were completely enclosed (figure 2). Because the fluorescence, near-sur- face bubbles, and stress spangles are typical of clarified material, it would appear that the original material from which n~ost,if not all, of the beads were fashioned was cloudy. Since these beads had properties similar to those of the cabochons described in the last issue, which faded when exposed to light, we fade tested one by placing it about 7.5 cm (3i nch- es) from the bulb of a 12-watt Tensor lamp for seven days. (Neighboring
light.) The selected bead failed to fade, which indicates that the material was not surface treated in the same man- ner as were the cabochons described in the Summer issue. At the time we tested the "fad- ing" amber cabochons, we also exposed one each of five pairs of close- ly matched, untreated Dominican amber cabochons to the Tensor lamp for a seven-day period. The control sample of each pair was kept in the dark during the exposure period. All but one of the exposed cabochons actually darliened. This reaction was not unexpected, since untreated amber typically darkens with time due to oxidation. Exposure to strong light apparently accelerates the process.