Glass Bangles
Recently, the Carlsbad laboratory was sent two bangles for identification: a 343.94 ct translucent white bangle and a 355.52 ct translucent mottled light purplish gray and green bangle (figure 1). The white bangle could have easily been given a sight identification of nephrite due to its color and dullness. But its refractive index (RI) of about 1.500 eliminated the possibility of nephrite, which has an RI of 1.62. Further observation showed an even color and no natural inclusions. Gas bubbles of various sizes could be seen just below the surface (figure 2). The RI in combination with the gas bubbles indicated that this bangle was a manufactured product.
The mottled bangle had a color very similar to that of jadeite. An RI of 1.610, rather than the typical jadeite RI of 1.66, indicated that this piece was also not what it appeared to be. Gas bubbles were identified throughout the bangle (figure 3), further confirming that this was a manufactured product. Strings of gas bubbles were observed without magnification, an arrangement that could have easily been mistaken for a natural jadeite structure (figure 4).
These gemological properties and observations identified these bangles as manmade glass and not the nephrite and jadeite they resembled. With nephrite and jadeite having such a rich cultural history, it is common for imitations to show up on the market. Items like these demonstrate the need to always be cautious when purchasing jewelry.
