Most gem zircons are found as waterworn pebbles in gravel deposits in Thailand, Cambodia, Vietnam, and Sri Lanka. They are typically brown, reddish-brown, green, or yellow in color. Virtually all zircon gemstones used in jewelry have been heat-treated to enhance their colors, producing blue, golden and some colorless stones. Zircon's dispersion and brilliance is almost as good as that of diamond. However, its inferior hardness and brittleness reaveal zircon as an imposter. It is unfortunate that zircon's reputation as a diamond simulant has undermined its popularity. Today natural zircon is sometimes confused with synthetic cubic zirconia, which is used in fashion jewelry to simulate diamond.
Image Number: 77-14891 Penland
Catalog Number: G2237,G3554,G3568,G2222
Weight: 97.6, 48.2, 106.1, 103.2 carats
G2222, G2237: Roebling Fund, 1943; G3554: Chamberlain Fund, 1959; G3568: Exchange, 1959